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{{Short description|Species of bird}} {{Good article}} {{Use dmy dates|date=September 2020}} {{very long|date=January 2024|words=19,000}} {{Speciesbox | image = Red-tailed Hawk (45812546121).jpg | image_caption = | image2 = Screaming Hawk.wav | image2_caption = Red-tailed hawk call | status = LC | status_system = IUCN3.1 | status_ref =<ref name=IUCN>{{cite iucn |author=BirdLife International |year=2016 |title=''Buteo jamaicensis'' |page=e.T22695933A93534834 |doi=10.2305/IUCN.UK.2016-3.RLTS.T22695933A93534834.en}}</ref> | status2 = G5 | status2_system = TNC | status2_ref =<ref name="NatureServe">{{cite web|title=Buteo jamaicensis|url=https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.103000/Buteo_jamaicensis|website=[[NatureServe]] Explorer|access-date=18 July 2024}}</ref> | taxon = Buteo jamaicensis | authority = ([[Johann Friedrich Gmelin|Gmelin]], 1788) | synonyms = ''Buteo borealis''<br/> ''Buteo borealis'' <small>(''[[lapsus]]'')</small><br /> ''Falco borealis'' <small>Gmelin</small><br /> ''Falco harlani'' <small>Audubon</small> | range_map = Buteo jamaicensis map.svg | range_map_caption = {{leftlegend|#FF7F2A|Breeding}}{{leftlegend|#7137C8|Year-round}}{{leftlegend|#5F8DD3|Nonbreeding}} }} The '''red-tailed hawk''' ('''''Buteo jamaicensis''''') is a [[bird of prey]] that breeds throughout most of North America, from the interior of [[Alaska]] and [[northern Canada]] to as far south as [[Panama]] and the [[West Indies]]. It is one of the most common members of the genus ''[[Buteo]]''.<ref name="Ferguson-Lees">{{cite book|year=2001|title=Raptors of the World| publisher=[[Helm Identification Guides|Christopher Helm]]|location=London|isbn=978-0-7136-8026-3|author1=Ferguson-Lees, J. |author2=Christie, D. }}</ref> The red-tailed hawk is one of three species colloquially known in the United States as the "[[Chickenhawk (bird)|chickenhawk]]", though it rarely preys on standard-sized chickens.<ref>{{cite web |url=http://www.allaboutbirds.org/guide/Red-tailed_Hawk/lifehistory |title=Red-tailed Hawk |work=All About Birds |publisher=Cornell University |access-date=16 May 2011}}</ref> Red-tailed hawks can acclimate to all the [[biome]]s within their range, occurring on the edges of non-ideal habitats such as dense forests and sandy deserts.<ref name="CRPreston">Preston, C. R. (2000). ''Red-tailed Hawk''. Stackpole Books.</ref> The red-tailed hawk occupies a wide range of habitats and altitudes, including [[desert]]s, [[grassland]]s, [[coniferous]] and [[deciduous]] forests, [[Agricultural land|agricultural fields]], and [[Urbanization|urban areas]]. Its latitudinal limits fall around the [[tree line]] in the [[subarctic]] and it is absent from the high [[Arctic]]. It favors varied habitats with [[Woodland|open woodland]], [[woodland edge]] and [[open terrain]]. It is legally protected in [[Canada]], [[Mexico]], and the United States by the [[Migratory Bird Treaty Act]]. The [[Red-tailed hawk#Subspecies|14 recognized subspecies]] vary in appearance and range, varying most often in color. In the west of North America, red-tails are often strongly [[Polymorphism (biology)|polymorphic]], with individuals ranging from almost white to nearly all black.<ref name= Palmer>Palmer, R. S., ed. (1988). ''Handbook of North American birds''. Volume 5 Diurnal Raptors (part 2).</ref> The subspecies [[Harlan's hawk]] (''B. j. harlani'') is sometimes considered a separate species (''B. harlani'').<ref name="Maxwell2013">{{cite book |last=Maxwell |first=Terry C. |year=2013 |title=Wildlife of the Concho Valley |publisher=Texas A&M University Press |isbn=978-1-62349-006-5 |page=148 |url=https://books.google.com/books?id=qVi9AAAAQBAJ&pg=PT148 }}</ref> The red-tailed hawk is one of the largest members of the genus ''Buteo'', typically weighing from {{Convert|690|to|1600|g|lb|abbr = on|sigfig=2}} and measuring {{Convert|45|-|65|cm|in|abbr = on}} in length, with a wingspan from {{Convert|110|-|141|cm|ftin|0|abbr = on}}. This species displays [[sexual dimorphism]] in size, with females averaging about 25% heavier than males.<ref name= Ferguson-Lees/><ref>{{cite encyclopedia |url=http://eol.org/pages/1049057/details |title=Red-tailed Hawk |encyclopedia=Encyclopedia of Life |access-date=21 March 2012}}</ref> The diet of red-tailed hawks is highly variable and reflects their status as opportunistic generalists, but in North America, they are most often predators of small [[mammal]]s such as [[rodent]]s; prey that is terrestrial and at least partially diurnal is preferred.<ref name=Schmutz>{{cite journal | last1=Schmutz | first1=J.K. | last2=Schmutz | first2=S.M. | last3=Boag | first3=D.A. | date=1 June 1980 | title=Coexistence of three species of hawks (''Buteo'' spp.) in the prairie–parkland ecotone | journal=Canadian Journal of Zoology | publisher=Canadian Science Publishing | volume=58 | issue=6 | pages=1075–1089 | issn=0008-4301 | doi=10.1139/z80-151 | pmid=7427802 | bibcode=1980CaJZ...58.1075S }}</ref> Like many ''Buteo'' species, they most often hunt from a perch, but they can vary their hunting techniques where prey and habitat demand it.<ref name="Palmer" /><ref name="Preston">Preston, C. R. and R. D. Beane. (2009). "Red-tailed Hawk (''Buteo jamaicensis''), ''The Birds of North America''. {{doi|10.2173/bna.52}}.</ref> Because they are so common and easily trained as capable hunters, in the United States they are the most commonly captured hawks for [[falconry]]. Falconers are permitted to take only passage hawks (which have left the nest, are on their own, but are less than a year old) so as to not affect the breeding population. Passage red-tailed hawks are also preferred by falconers because they have not yet developed the adult behaviors that would make them more difficult to train.<ref name="Beebe">Beebe, F. L. (1976). ''North American Falconry and Hunting Hawks''. Hancock House Books (British Columbia).</ref> == Taxonomy == The red-tailed hawk was [[species description|formally described]] in 1788 by German naturalist [[Johann Friedrich Gmelin]] under the [[binomial name]] ''Falco jamaicensis''.<ref>{{ cite book | last=Gmelin | first=Johann Friedrich | author-link=Johann Friedrich Gmelin| year=1788 | title=''Systema naturae per regna tria naturae : secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis'' | edition=13th | volume=1, Part 1 | language=la | place=Lipsiae [Leipzig] | publisher=Georg. Emanuel. Beer | page=266 | url=https://www.biodiversitylibrary.org/page/25751486 }}</ref> Gmelin based his description on the "cream-coloured buzzard" described in 1781 by [[John Latham (ornithologist)|John Latham]] in his ''A General Synopsis of Birds''.<ref>{{cite book | last=Latham | first=John | author-link=John Latham (ornithologist) | year=1781 | title=A General Synopsis of Birds | volume=1 |department=Part 1 | pages=49–50 | place=London, UK | publisher= Printed for Benj. White | url=https://www.biodiversitylibrary.org/page/33727557 }}</ref> The [[type locality (biology)|type locality]] is Jamaica.<ref>{{ cite book | editor1-last=Mayr | editor1-first=Ernst | editor1-link=Ernst Mayr | editor2-last=Cottrell | editor2-first=G. William | year=1979 | title=Check-List of Birds of the World | volume=1 | edition=2nd | publisher=[[Museum of Comparative Zoology]] | place=Cambridge, MA | page=371 | url=https://www.biodiversitylibrary.org/page/16109011 }}</ref> The red-tailed hawk is now placed in the [[genus]] ''Buteo'' that was erected by French naturalist [[Bernard Germain de Lacépède]] in 1799.<ref>{{ cite book | last=Lacépède | first=Bernard Germain de | author-link=Bernard Germain de Lacépède | year=1799 | chapter=Tableau des sous-classes, divisions, sous-division, ordres et genres des oiseux | title=Discours d'ouverture et de clôture du cours d'histoire naturelle | lang=fr | publisher=Plassan | place=Paris | page=4 | chapter-url=https://books.google.com/books?id=6uhAAAAAcAAJ&pg=RA3-PA4 }} Page numbering starts at one for each of the three sections.</ref><ref name=ioc>{{cite web | editor1-last=Gill | editor1-first=Frank | editor1-link=Frank Gill (ornithologist) | editor2-last=Donsker | editor2-first=David | editor3-last=Rasmussen | editor3-first=Pamela | editor3-link=Pamela Rasmussen | year=2020 | title=Hoatzin, New World vultures, Secretarybird, raptors | series=IOC World Bird List |edition=vers 10.2 | publisher=[[International Ornithologists' Union]] | url=https://www.worldbirdnames.org/bow/raptors/ | access-date=9 October 2020 }}</ref> [[File:Red-tailed hawk in flight.jpg|thumb|right|In flight showing the red tail]] [[File:Hawk hovers.ogv|thumb|A red-tailed hawk hovers in the wind.]] The red-tailed hawk is a member of the subfamily [[Buteoninae]], which includes about 55 currently recognized species.<ref name= Ferguson-Lees/><ref name= delHoyo/> Unlike many lineages of accipitrids, which seemed to have radiated out of Africa or south Asia, the Buteoninae clearly originated in the Americas based on fossil records and current species distributions (more than 75% of the extant hawks from this lineage are found in the Americas).<ref name= Ferguson-Lees/><ref>Brodkorb, P. (1964). ''Catalogue of fossil birds: Part 2 (Anseriformes through Galliformes)''. University of Florida.</ref> As a subfamily, the Buteoninae seem to be rather old based on genetic materials, with [[monophyletic]] genera bearing several million years of individual evolution. Diverse in plumage appearance, habitat, prey, and nesting preferences, buteonine hawks are nonetheless typically medium- to large-sized hawks with ample wings (while some fossil forms are very large, larger than any eagle alive today).<ref>{{cite journal | last1=Lerner| first1=Heather R. L. | last2=Klaver | first2=Matthew C. | last3=Mindell | first3=David P. | title=Molecular phylogenetics of the Buteonine birds of prey (Accipitridae)| journal=The Auk | volume=125 | issue=2 | year=2008 | issn=0004-8038 | doi=10.1525/auk.2008.06161|url=https://www.researchgate.net/publication/228375177| pages=304–315| s2cid=85907449 | doi-access=free }}</ref><ref>{{cite journal | last1=de Oliveira | first1=Edivaldo Herculano C. | last2=Tagliarini | first2=Marcella Mergulhão | last3=dos Santos | first3=Michelly S. | last4=O'Brien | first4=Patricia C. M. | last5=Ferguson-Smith | first5=Malcolm A. | title=Chromosome Painting in Three Species of Buteoninae: A Cytogenetic Signature Reinforces the Monophyly of South American Species | journal=PLOS ONE|volume=8 | issue=7 | date=26 July 2013 | issn=1932-6203 | doi=10.1371/journal.pone.0070071|doi-access=free | page=e70071| pmid=23922908 | pmc=3724671 | bibcode=2013PLoSO...870071D }}</ref><ref>{{cite journal|last=Suarez|first=William|year=2004|title=The Identity of the Fossil Raptor of the Genus ''Amplibuteo'' (Aves: Accipitridae) from the Quaternary of Cuba|journal=Caribbean Journal of Science|volume=40|issue=1|pages=120–125|url=http://caribjsci.org/april%2004/40_120-125.pdf}}</ref> The red-tailed hawk is a member of the [[genus]] ''Buteo'', a group of medium-sized raptors with robust bodies and broad wings. Members of this genus are known as "buzzards" in Eurasia, but "hawks" in North America.<ref name="ITIS">{{ITIS |id=175350 |taxon=''Buteo jamaicensis'' (J. F. Gmelin, 1788)}}</ref> Under current classification, the genus includes about 29 species, the second-most diverse of all extant accipitrid genera behind only ''[[Accipiter]]''.<ref name="ioc" /> The buzzards of Eurasia and Africa are mostly part of the genus ''Buteo'', although two other small genera within the subfamily Buteoninae occur in Africa.<ref name="Ferguson-Lees" /><ref name="delHoyo" /><ref name="Riesing">{{cite journal | last1=Riesing | first1=Martin J | last2=Kruckenhauser | first2=Luise | last3=Gamauf | first3=Anita | last4=Haring | first4=Elisabeth | title=Molecular phylogeny of the genus Buteo (''Aves: Accipitridae'') based on mitochondrial marker sequences | journal=Molecular Phylogenetics and Evolution| volume=27 | issue=2 | year=2003 | issn=1055-7903 | doi=10.1016/s1055-7903(02)00450-5 | pages=328–342| pmid=12695095 | bibcode=2003MolPE..27..328R }}</ref> At one time, the [[rufous-tailed hawk]] (''B. ventralis''), distributed in [[Patagonia]] and some other areas of southern South America, was considered part of the red-tailed hawk species. With a massive distributional gap consisting of most of South America, the rufous-tailed hawk is considered a separate species now, but the two hawks still form a [[Species complex|"species pair" or superspecies]], as they are clearly closely related. The rufous-tailed hawk, while comparatively little studied, is very similar to the red-tailed hawk, being about the same size and possessing the same wing structure, and having more or less parallel nesting and hunting habits. Physically, however, rufous-tailed hawk adults do not attain a bright brick-red tail as do red-tailed hawks, instead retaining a dark brownish-cinnamon tail with many blackish crossbars similar to juvenile red-tailed hawks.<ref name="Ferguson-Lees" /><ref>{{cite journal | last1=Johnson | first1=Ned K. | last2=Peeters | first2=Hans J. | title=The Systematic Position of Certain Hawks in the Genus ''Buteo'' | journal=The Auk | volume=80 | issue=4 | year=1963 | issn=0004-8038 | doi=10.2307/4082848|jstor=4082848|url=http://www.raptors-international.org/book/birds_of_prey_1986/Clark_1986_115-118.pdf | pages=417–446}}</ref><ref> {{cite journal |last=Clark |first=W.S. |year=1986 |title=What is ''Buteo ventralis?'' |journal=[[Birds Prey Bulletin]] |volume= 3|pages= 115–118|url=http://www.raptors-international.org/book/birds_of_prey_1986/Clark_1986_115-118.pdf}}</ref> Another, more well-known, close relative to the red-tailed hawk is the [[common buzzard]] (''B. buteo''), which has been considered as its Eurasian "[[Ecological niche|broad ecological counterpart]]" and may also be within a species complex with red-tailed hawks. The common buzzard, in turn, is also part of a species complex with other Old World buzzards, namely the [[mountain buzzard]] (''B. oreophilus''), the [[forest buzzard]] (''B. trizonatus'' ), and the [[Madagascar buzzard]] (''B. brachypterus'').<ref name="Ferguson-Lees" /><ref name="Riesing" /><ref>{{cite journal |last=Clark |first=W.S. |year=2007 |title=Taxonomic status of the Forest Buzzard ''Buteo oreophilus trizonatus'' |journal=Ostrich |volume=78 |issue=1 |pages=101–104 |doi=10.2989/OSTRICH.2007.78.1.16.60 |bibcode=2007Ostri..78..101C |s2cid=6270968 |url=http://www.globalraptors.org/grin/researchers/uploads/155/fbostrich_78(1)_clark.pdf |url-status=dead |access-date=13 February 2019 |archive-url=https://web.archive.org/web/20210831200441/http://www.globalraptors.org/grin/researchers/uploads/155/fbostrich_78(1)_clark.pdf |archive-date=31 August 2021 }}</ref> All six species, although varying notably in size and plumage characteristics, in the alleged species complex that contains the red-tailed hawk share with it the feature of the blackish patagium marking, which is missing in most other ''Buteo'' spp.<ref name="Ferguson-Lees" /><ref>{{cite journal | last1=Kruckenhauser | first1=Luise | last2=Haring | first2=Elisabeth | last3=Pinsker | first3=Wilhelm | last4=Riesing | first4=Martin J. | last5=Winkler | first5=Hans | last6=Wink | first6=Michael | last7=Gamauf | first7=Anita | title=Genetic vs. morphological differentiation of Old World buzzards (genus ''Buteo'', ''Accipitridae'') | journal=Zoologica Scripta| volume=33 | issue=3 | year=2004 | issn=0300-3256 | doi=10.1111/j.0300-3256.2004.00147.x | pages=197–211| s2cid=84053997 }}</ref> ===Subspecies=== At least 14 recognized subspecies of ''B. jamaicensis'' are described, which vary in range and in coloration. Not all authors accept every subspecies, though, particularly some of the insular races of the tropics (which differ only slightly in some cases from the nearest mainland forms) and particularly Krider's hawk – by far the most controversial red-tailed hawk race, as few authors agree on its suitability as a full-fledged subspecies.<ref name= Palmer/><ref name= Preston/><ref name= Brown/> {| class="wikitable " |- ! Image !! Subspecies !! Distribution |- |[[File:Red-tailed Hawk Buteo jamaicensis 2423.jpg|120px]] ||[[Jamaican red-tailed hawk]] (''B. j. jamaicensis'')||occurs throughout the [[West Indies]] (including Jamaica, [[Hispaniola]], [[Puerto Rico]] and the [[Lesser Antilles]]) except for the Bahamas and Cuba. |- |[[File:Red-tailed hawk, Swan Lake, Victoria, BC (9346135799).jpg|120px]] ||[[Alaska red-tailed hawk]] (''B. j. alascensis'') ||breeds (probably resident) from southeastern coastal [[Alaska]] to [[Haida Gwaii]] and [[Vancouver Island]] in British Columbia. |- |[[File:Red-tailed Hawk (Buteo jamaicensis) (12059507526).jpg|120px]] || [[Eastern red-tailed hawk]] (''B. j. borealis'') ||breeds from southeast Canada and [[Maine]] south through [[Texas]] and east to [[northern Florida]]. |- |[[File:Buteo jamaicensis -Pillar Point Harbor, California, USA-8.jpg|120px]] ||[[Western red-tailed hawk]] (''B. j. calurus'') || greatest longitudinal breeding distribution of any race of red-tailed hawk. |- |[[File:Buteo jamaicensis costaricensis 2392995.jpg|120px]] ||[[Central American red-tailed hawk]] (''B. j. costaricensis'') || from Nicaragua to Panama. |- |[[File:Red-taied Hawk (Fuertes's) Buteo jamaicensis fuertesi (16273651968).jpg|120px]] ||[[Southwestern red-tailed hawk]] (''B. j. fuertesi'') ||breeds from northern [[Chihuahua (state)|Chihuahua]] to [[South Texas]]. |- | ||[[Tres Marias red-tailed hawk]] (''B. j. fumosus'') || endemic to [[Islas Marías]], Mexico. |- | ||[[Mexican Highlands red-tailed hawk]] (''B. j. hadropus'') || native to the Mexican Highlands. |- |[[File:Harlan's Red-tailed Hawk (Buteo jamaicensis harlini) (16552869585).jpg|120px]] ||[[Harlan's hawk]] (''B. j. harlani'') ||breeds from central Alaska to northwestern Canada, with the largest number of birds breeding in the [[Yukon]] or western Alaska, reaching their southern limit in north-central [[British Columbia]]. |- | ||[[Red-tailed hawk (kemsiesi)|Red-tailed hawk (''kemsiesi'')]] (''B. j. kemsiesi)'' || a dark subspecies resident from [[Chiapas]], [[Mexico]], to [[Nicaragua]]. |- |[[File:Buteo jamaicensis kriderii 58239568.jpg|120px]] ||[[Krider's hawk]] (''B. j. kriderii'') ||breeds from southern [[Alberta]], southern [[Saskatchewan]], southern [[Manitoba]], and extreme western [[Ontario]] south to south-central [[Montana]], [[Wyoming]], western [[Nebraska]], and western [[Minnesota]]. |- | ||[[Socorro red-tailed hawk]] (''B. j. socorroensis)'' || endemic to [[Socorro Island]], Mexico. |- | ||[[Cuban red-tailed hawk]] (''B. j. solitudinis'') || native to the Bahamas and Cuba. |- |[[File:Buteo jamaicensis Vero Beach.jpg|120px]] ||[[Florida red-tailed hawk]] (''B. j. umbrinus)'' ||occurs year-round in peninsular Florida north to as far [[Tampa Bay]] and the [[Kissimmee Prairie Preserve State Park|Kissimmee Prairie]] south throughout the rest of peninsular Florida south to the [[Florida Keys]]. |- |} == Description == [[File:Buteo jamaicensis -John Heinz National Wildlife Refuge at Tinicum, Pennsylvania, USA-8.jpg|thumb|A red-tailed hawk at [[John Heinz National Wildlife Refuge at Tinicum]]]] Red-tailed hawk [[plumage]] can be variable, depending on the [[subspecies]] and the region. These color variations are [[Polymorphism (biology)|morphs]], and are not related to [[molt]]ing. The western North American population, ''B. j. calurus'', is the most variable subspecies and has three main color morphs: light, dark, and intermediate or rufous. The dark and intermediate morphs constitute 10–20% of the population in the Western United States, but seem to constitute only 1–2% of ''B. j. calurus'' in western Canada.<ref name="Land" /><ref name= Clark>Clark, W.S. (2014). [http://www.globalraptors.org/grin/researchers/uploads/155/harlansplumagesdifferrev2-14_(1).pdf HARLAN’S HAWK differs from RED-TAILED HAWK] {{Webarchive|url=https://web.archive.org/web/20190213124046/http://www.globalraptors.org/grin/researchers/uploads/155/harlansplumagesdifferrev2-14_(1).pdf |date=13 February 2019 }}. Global Raptor Information Network.</ref> A whitish underbelly with a dark brown band across the belly, formed by horizontal streaks in [[feather]] patterning, is present in most color variations. This feature is variable in eastern hawks and generally absent in some light subspecies (i.e. ''B. j. fuertesi'').<ref name="Ferguson-Lees" /> Most adult red-tails have a dark-brown nape and upper head, which gives them a somewhat hooded appearance, while the throat can variably present a lighter brown "necklace". Especially in younger birds, the underside may be otherwise covered with dark-brown spotting, and some adults may too manifest this stippling. The back is usually a slightly darker brown than elsewhere with paler scapular feathers, ranging from tawny to white, forming a variable imperfect "V" on the back. The tail of most adults, which gives this species its name, is rufous brick-red above with a variably sized, black subterminal band and generally appears light buff-orange from below. In comparison, the typical pale immatures (i.e., less than two years old) typically have a slightly paler head and tend to show a darker back than adults with more apparent pale wing-feather edges above (for descriptions of dark morph juveniles from ''B. j. calurus'', which is also generally apt for description of rare dark morphs of other races, see under that subspecies description). In immature red-tailed hawks of all morphs, the tail is a light brown above with numerous small dark brown bars of roughly equal width, but these tend to be much broader on dark morph birds. Even in young red-tails, the tail may be a somewhat rufous tinge of brown.<ref name="Ferguson-Lees" /><ref name="CRPreston" /><ref name="USGS">{{cite web|url=http://www.mbr-pwrc.usgs.gov/Infocenter/i3370id.html|title=''Buteo jamaicensis''|publisher=U.S. Geological Survey|access-date=5 June 2007|archive-date=6 January 2016|archive-url=https://web.archive.org/web/20160106032548/http://www.mbr-pwrc.usgs.gov/Infocenter/i3370id.html|url-status=dead}}</ref> The [[beak|bill]] is relatively short and dark, in the hooked shape characteristic of [[Bird of prey|raptors]], and the head can sometimes appear small in size against the thick body frame.<ref name="Ferguson-Lees" /> The [[cere]], the legs, and the feet of the red-tailed hawk are all yellow, as is the color of bare parts in many accipitrids of different lineages.<ref name="ADW">{{cite web|url=http://animaldiversity.ummz.umich.edu/site/accounts/information/Buteo_jamaicensis.html|last1=Dewey |first1= T. |first2= D. |last2=Arnold |title=''Buteo jamaicensis''|access-date=5 June 2007 |publisher=Animal Diversity Web}}</ref> Immature birds can be readily identified at close range by their yellowish [[Iris (anatomy)|irises]]. As the bird attains full maturity over the course of 3–4 years, the iris slowly darkens into a reddish-brown, which is the adult eye-color in all races.<ref name="CRPreston" /><ref name="USGS" /> Seen in flight, adults usually have dark brown along the lower edge of the wings, against a mostly pale wing, which bares light brownish barring. Individually, the underwing coverts can range from all dark to off-whitish (most often more heavily streaked with brown) which contrasts with a distinctive black [[patagium]] marking. The wing coloring of adults and immatures is similar but for typical pale morph immatures having somewhat heavier brownish markings.<ref name="Ferguson-Lees" /><ref name="Brown">Brown, Leslie and Amadon, Dean (1986) ''Eagles, Hawks and Falcons of the World''. The Wellfleet Press. {{ISBN|978-1555214722}}.</ref> [[File:Buteo jamaicensis in flight at Llano Seco-1520.jpg|thumb|upright=1.8|A western juvenile in flight]] Though the markings and color vary across the subspecies, the basic appearance of the red-tailed hawk is relatively consistent. Overall, this species is blocky and broad in shape, often appearing (and being) heavier than other ''[[Buteo]]s'' of similar length. They are the heaviest ''Buteos'' on average in eastern North America, albeit scarcely ahead of the larger winged [[rough-legged buzzard]] (''Buteo lagopus''), and second only in size in the west to the [[ferruginous hawk]] (''Buteo regalis''). Red-tailed hawks may be anywhere from the fifth to the ninth heaviest ''Buteo'' in the world depending on what figures are used. However, in the northwestern United States, ferruginous hawk females are 35% heavier than female red-tails from the same area.<ref name= Ferguson-Lees /> On average, western red-tailed hawks are relatively longer winged and lankier proportioned but are slightly less stocky, compact and heavy than eastern red-tailed hawks in North America. Eastern hawks may also have mildly larger talons and bills than western ones. Based on comparisons of morphology and function among all accipitrids, these features imply that western red-tails may need to vary their hunting more frequently to on the wing as the habitat diversifies to more open situations and presumably would hunt more variable and faster prey, whereas the birds of the east, which was historically well-wooded, are more dedicated perch hunters and can take somewhat larger prey but are likely more dedicated mammal hunters.<ref name= Preston/><ref name= Pearlstine>{{cite journal|last1=Pearlstine |first1=E.V. |last2=Thompson |first2=D.B. |year=2004|title=Geographic variation in morphology of four species of migratory raptors |url=https://sora.unm.edu/node/54133 |journal=[[Journal of Raptor Research]] |volume= 38|pages= 334–342}}</ref><ref name= Fitzpatrick>{{cite journal|last1=Fitzpatrick|first1=B. M.|last2=Dunk|first2=J. R. |year=1999|title=Ecogeographic variation in morphology of Red-tailed Hawks in western North America|journal=Journal of Raptor Research|volume= 33|issue=4|pages= 305–312|url=https://sora.unm.edu/node/53774}}</ref> In terms of size variation, red-tailed hawks run almost contrary to [[Bergmann's rule]] (i.e. that northern animals should be larger in relation than those closer to the [[Equator]] within a species) as one of the northernmost subspecies, ''B. j. alascensis'', is the second smallest race based on linear dimensions and that two of the most southerly occurring races in the United States, ''B. j. fuertesi'' and ''B. j. umbrinus'', respectively, are the largest proportioned of all red-tailed hawks.<ref name="Preston" /><ref name="Fitzpatrick" /><ref>{{cite journal |last1=Meiri |first1=S. |last2=Dayan |first2=T. |year=2003 |title=On the validity of Bergmann's rule |journal=[[Journal of Biogeography]] |volume=30 |issue=3 |pages=331–351 |doi=10.1046/j.1365-2699.2003.00837.x |bibcode=2003JBiog..30..331M |s2cid=11954818 }}</ref> Red-tailed hawks tend have a relatively short but broad tails and thick, chunky wings.<ref name="USGS" /> Although often described as long-winged,<ref name="Ferguson-Lees" /><ref name="CRPreston" /> the proportional size of the wings is quite small and red-tails have high [[wing loading]] for a buteonine hawk. For comparison, two other widespread ''Buteo'' hawks in North America were found to weigh: {{convert|30|g|oz|abbr=on}} for every square centimeter of wing area in the [[rough-legged buzzard]] (''B. lagopus'') and {{convert|44|g|oz|abbr=on}}/cm<sup>2</sup> in the [[red-shouldered hawk]] (''B. lineatus''). In contrast, the red-tailed hawk weighed considerably more for their wing area: {{convert|199|g|oz|abbr=on}} per square cm.<ref>{{cite journal |last1=Jaksić |first1=F.M. |last2=Carothers |first2=J.H. |year=1985 |title=Ecological, morphological, and bioenergetic correlates of hunting mode in hawks and owls |journal=[[Ornis Scandinavica]] |volume=16 |issue=3 |pages=165–172 |doi=10.2307/3676627 |jstor=3676627 }}</ref> [[File:Milwaukee Public Museum March 2023 74 (Wisconsin Birds--Wisconsin Fields and Woods, Red-Tailed Hawk).jpg|thumb|Taxidermied red-tailed hawk at the [[Milwaukee Public Museum]]]] As is the case with many raptors, the red-tailed hawk displays sexual dimorphism in size, as females are on average 25% larger than males.<ref name="ADW" /> As is typical in large raptors, frequently reported mean body mass for red-tailed hawks is somewhat higher than expansive research reveals.<ref name= Hull>{{Cite journal | pmid = 18208488 | year = 2008 | last1 = Hull | first1 = J. M. | title = Landscape characteristics influence morphological and genetic differentiation in a widespread raptor (''Buteo jamaicensis'') | journal = Molecular Ecology | volume = 17 | issue = 3 | pages = 810–24 | last2 = Hull | first2 = A. C. | last3 = Sacks | first3 = B. N. | last4 = Smith | first4 = J. P. | last5 = Ernest | first5 = H. B. | doi = 10.1111/j.1365-294X.2007.03632.x | bibcode = 2008MolEc..17..810H | s2cid = 26662247 }}</ref> Part of this weight variation is seasonal fluctuations; hawks tend to be heavier in winter than during migration or especially during the trying summer breeding season, and also due to clinal variation. Furthermore, immature hawks are usually lighter in mass than their adult counterparts despite having somewhat longer wings and tails. Male red-tailed hawks may weigh from {{convert|690|to|1300|g|lb|abbr=on}} and females may weigh {{convert|801|to|1723|g|lb|abbr=on}} (the lowest figure from a migrating female immature from [[Goshute Mountains]], [[Nevada]], the highest from a wintering female in [[Wisconsin]]).<ref name= Palmer/><ref name= delHoyo>{{cite book |editor-last = del Hoyo |editor-first = J. |editor2-last = Elliott |editor2-first = A. | editor3-last = Sargatal |editor3-first = J. |year = 1999 |title = Handbook of the Birds of the World |volume = 2 |publisher = Lynx Edicions |location = Barcelona |isbn = 978-84-87334-15-3|title-link = Handbook of the Birds of the World }}</ref><ref name= Donohue>{{cite journal |last1=Donohue |first1=K.C. |last2=Dufty |first2=A.M. |year=2006 |title=Sex determination of Red-tailed Hawks (''Buteo jamaicensis calurus'') using DNA analysis and morphometrics |journal=[[Journal of Field Ornithology]] |volume=77 |issue=1 |pages=74–79 |doi=10.1111/j.1557-9263.2006.00003.x |doi-access=free |jstor=27639302 |url=https://scholarworks.boisestate.edu/cgi/viewcontent.cgi?article=1010&context=bio_facpubs |url-access=subscription }}</ref> Some sources claim the largest females can weigh up to {{convert|2000|g|lb|abbr=on}}, but whether this is in reference to wild hawks (as opposed to those in captivity or used for falconry) is not clear.<ref>{{cite web |title=Buteos |website=adfg.alaska.gov |publisher=[[Alaska Department of Fish & Game]] |url=https://www.adfg.alaska.gov/static/education/wns/buteos.pdf |access-date=2018-01-08}}</ref> The largest known survey of body mass in red-tailed hawks is still credited to Craighead and Craighead (1956), who found 100 males to average {{convert|1028|g|lb|abbr=on}} and 108 females to average {{convert|1244|g|lb|abbr=on}}. However, these figures were apparently taken from labels on museum specimens, from natural history collections in [[Wisconsin]] and [[Pennsylvania]], without note to the region, age, or subspecies of the specimens.<ref name="Palmer" /><ref name="Craighead">Craighead, J. J. and F. C. Craighead, Jr. (1956). ''Hawks, owls and wildlife''. Stackpole Co. Harrisburg, PA.</ref> However, 16 sources ranging in sample size from the aforementioned 208 specimens to only four hawks in [[Puerto Rico]] (with 9 of the 16 studies of migrating red-tails), showed that males weigh a mean of {{convert|860.2|g|lb|abbr=on}} and females weigh a mean of {{convert|1036.2|g|lb|abbr=on}}, about 15% lighter than prior species-wide published weights. Within the [[continental United States]], typical weights of males can range from {{convert|840.8|g|lb|abbr=on}} (for migrating males in [[Chelan County, Washington]]) to {{convert|1031|g|lb|abbr=on}} (for male hawks found dead in [[Massachusetts]]), and females ranged from {{convert|1057.9|g|lb|abbr=on}} (migrants in the [[Goshute Mountains|Goshutes]]) to {{convert|1373|g|lb|abbr=on}} (for females diagnosed as ''B. j. borealis'' in western [[Kansas]]).<ref name="Hull" /><ref name="Preston" /><ref name="Pearlstine" /><ref name="Snyder">Snyder, N. F. R. and Wiley, J. W. (1976). [http://globalraptors.org/grin/researchers/uploads/470/snyder_&_wiley_1976.pdf "Sexual size dimorphism in hawks and owls of North America"] {{Webarchive|url=https://web.archive.org/web/20171020084150/http://globalraptors.org/grin/researchers/uploads/470/snyder_%26_wiley_1976.pdf |date=20 October 2017 }}. ''Ornithological Monographs'', Vol. 20, pp. i–vi, 1–96.</ref><ref>{{cite journal|doi=10.1676/13-131.1|title=Sex and Age Group Specific Changes in Body Condition of Red-tailed Hawks in Central Nebraska |journal=[[The Wilson Journal of Ornithology]] |volume=126|issue=3|pages=575–580|year=2014|last1=Schoenebeck|first1=Casey W.|last2=Turco|first2=Matthew|last3=Fahrlander|first3=Rae M.|last4=Darveau|first4=Kaitlyn M.|last5=Freeman|first5=Thomas L.|s2cid=84140038}}</ref><ref name="Steenhof">{{cite journal|doi=10.2307/4761|jstor=4761|title=Dietary Responses of Three Raptor Species to Changing Prey Densities in a Natural Environment|journal=The Journal of Animal Ecology|volume=57|issue=1|pages=37–48|year=1988|last1=Steenhof|first1=Karen|last2=Kochert|first2=Michael N.|bibcode=1988JAnEc..57...37S |url=https://zenodo.org/record/1235199}}</ref><ref>{{cite journal |last1=Franson |first1=J.C. |last2=Thomas |first2=N.J. |last3=Smith |first3=M.R. |last4=Robbins |first4=A.H. |last5=Newman |first5=S. |last6=McCartin |first6=P.C. |year=1996 |title=A retrospective study of postmortem findings in red-tailed hawks |journal=[[Journal of Raptor Research]] |volume= 30 |issue=1 |pages= 7–14 |bibcode=1996JRapR..30....7F |url=https://sora.unm.edu/node/53510 }}</ref><ref name="Imler">{{cite journal |last=Imler |first=R.H. |year=1937 |title=Weights of some birds of prey of western Kansas |journal=[[Bird Banding]] |volume= 8 |issue=4 |pages=166–169 |doi=10.2307/4509472|jstor=4509472 |url=https://sora.unm.edu/sites/default/files/journals/jfo/v008n04/p0166-p0169.pdf }}</ref> Size variation in body mass reveals that the red-tailed hawk typically varies only a modest amount and that size differences are geographically inconsistent.<ref name="Preston" /><ref name="Snyder" /> Male red-tailed hawks can measure {{convert|45|to|60|cm|in|abbr=on}} in total length, females measuring {{convert|48|to|65|cm|abbr=on}} long. Their wingspan typically can range from {{convert|105|to|141|cm|ftin|0|abbr=on}}, although the largest females may possible span up to {{convert|147|cm|ftin|0|abbr=on}}. In the standard scientific method of measuring wing size, the [[Wing chord (biology)|wing chord]] is {{convert|325.1|-|444.5|mm|in|abbr=on}} long. The tail measures {{convert|188|to|258.7|mm|in|abbr=on}} in length.<ref name= Ferguson-Lees/><ref name= delHoyo/><ref>[http://www.arkive.org/red-tailed-hawk/buteo-jamaicensis/#text=Facts|ARKive- Red-tailed Hawk videos, photos and facts] {{Webarchive|url=https://web.archive.org/web/20120604154344/http://www.arkive.org/red-tailed-hawk/buteo-jamaicensis/#text=Facts%7CARKive- |date=4 June 2012 }}. Arkive.org. Retrieved 2012-08-22.</ref> The [[Culmen (bird)|exposed culmen]] was reported to range from {{convert|21.7|to|30.2|mm|in|abbr=on}} and the [[Tibiotarsus|tarsus]] averaged {{convert|74.7|-|95.8|mm|in|abbr=on}} across the races.<ref name= Hull/><ref name= Preston/><ref>{{cite journal|url=http://scholarworks.boisestate.edu/bio_facpubs/11/|title=Sex Determination of Red-Tailed Hawks (''Buteo jamaicensis calurus'')|volume=77|pages=74–79|journal=Scholarworks.boisestate.edu|date=2006-02-27|doi=10.1111/j.1557-9263.2006.00003.x|last1=Donohue|first1=Kara C.|last2=Dufty|first2=Alfred M.|doi-access=free|url-access=subscription}}</ref> The middle toe (excluding talon) can range from {{convert|38.3|to|53.8|mm|in|abbr=on}}, with the hallux-claw (the talon of the rear toe, which has evolved to be the largest in accipitrids) measuring from {{convert|24.1|to|33.6|mm|in|abbr=on}} in length.<ref name= Hull/><ref name= Preston/> ===Identification=== [[File:Red-tailed hawk in Central Park (24796).jpg|thumb|Close-up of red-tailed hawk's head]] [[File:RedTailDisplay.jpg|thumb|Characteristic red tail]] [[File:red-tail hawk.webm|thumb|thumbtime=14|This [[red-tailed hawk]] is an ambassador animal for the Ohio Wildlife Center]] Although they overlap in range with most other American diurnal raptors, identifying most mature red-tailed hawks to species is relatively straightforward, particularly if viewing a typical adult at a reasonable distance. The red-tailed hawk is the only North American hawk with a rufous tail and a blackish [[patagium]] marking on the leading edge of its wing (which is obscured only on dark morph adults and Harlan's hawks by similarly dark-colored feathers).<ref name= Ferguson-Lees/> Other larger adult ''Buteo'' spp. in North America usually have obvious distinct markings that are absent in red-tails, whether the rufous-brown "beard" of [[Swainson's hawk]]s (''B. swainsonii'') or the colorful rufous belly and shoulder markings and striking black-and-white mantle of [[red-shouldered hawk]]s (also the small "windows" seen at the end of their primaries).<ref name="Robbins">{{cite book |last1=Robbins |first1=C.S. |last2=Bruun |first2=B. |last3=Zim |first3=H.S. |year=2001 |title=Birds of North America: A guide to field identification |publisher=Macmillan }}</ref> In perched individuals, even as silhouettes, the shape of large ''Buteo'' spp. may be distinctive, such as the wingtips overhanging the tail in several other species, but not in red-tails. North American ''Buteo'' spp. range from the dainty, compact builds of much smaller ones, such as [[broad-winged hawk]] (''B. platypterus'') to the heavyset, neckless look of [[ferruginous hawk]]s or the [[rough-legged buzzard]]s, which have a compact, smaller appearance than a red-tail in perched birds due to its small bill, short neck, and much shorter tarsi, while the opposite effect occurs in flying rough-legs with their much bigger wing area.<ref name="Ferguson-Lees" /><ref name="Robbins" /> In flight, most other large North American ''Buteo'' spp. are distinctly longer and more slender-winged than red-tailed hawks, with the much paler ferruginous hawk having peculiarly slender wings in relation to its massive, chunky body. Swainson's hawks are distinctly darker on the wing and ferruginous hawks are much paler-winged than typical red-tailed hawks. Pale morph adult ferruginous hawk can show mildly tawny-pink (but never truly rufous) upper tail, and like red-tails tend to have dark markings on underwing-coverts and can have a dark belly band, but compared to red-tailed hawks have a distinctly broader head, their [[Flight feathers|remiges]] are much whiter looking with very small, dark primary tips, they lack the red-tail's diagnostic patagial marks and usually also lack the dark subterminal tail-band, and ferruginous hawks have totally feathered tarsi. With its whitish head, the ferruginous hawk is most similar to Krider's red-tailed hawks, especially in immature plumage, but the larger hawk has broader head and narrower wing shape, and the ferruginous immatures are paler underneath and on their legs. Several species share a belly band with the typical red-tailed hawk, but they vary from subtle (as in the ferruginous hawk) to solid blackish, the latter in most light-morph [[rough-legged buzzard]]s.<ref name="Ferguson-Lees" /><ref name="Brown" /> More difficult to identify among adult red-tails are their darkest variations, as most species of ''Buteo'' in North America also have dark morphs. Western dark morph red-tails (i.e. ''B. j. calurus'') adults, however, retain the typical distinctive brick-red tail, which other species lack, and may stand out even more against the otherwise all chocolate-brown to black bird. Standard pale juveniles when perched show a whitish patch in the outer half of the upper surface of the wing, which other juvenile ''Buteo'' spp. lack.<ref name="CRPreston" /> The most difficult to identify stages and plumage types are dark morph juveniles, Harlan's hawk and some Krider's hawks (the latter mainly with typical ferruginous hawks as mentioned). Some darker juveniles are similar enough to other ''Buteo'' juveniles that they "cannot be identified to species with any confidence under various field conditions."<ref name="Palmer" /><ref name="CRPreston" /> However, field identification techniques have advanced in the last few decades and most experienced hawk-watchers can distinguish even the most vexingly plumaged immature hawks, especially as the wing shapes of each species becomes apparent after seeing many. Harlan's hawks are most similar to dark morph [[rough-legged buzzard]]s and dark morph [[ferruginous hawk]]s. Wing shape is the most reliable identification tool for distinguishing Harlan's hawks from these, but also the pale streaking on the breast of Harlan's, which tends to be conspicuous in most individuals, and is lacking in the other hawks. Also, dark morph ferruginous hawks do not have the dark subterminal band of a Harlan's hawk, but do bear a black undertail covert lacking in Harlan's.<ref name="Ferguson-Lees" /><ref name="Harlan">{{cite journal |last1=Liguori |first1=J. |last2=Sullivan |first2=B.L.|year=2010|title=Comparison of Harlan's hawk with Eastern & Western Red-tailed Hawks|journal=Birding|pages=30–37}}</ref> [[File:Red-tailed Hawk, Fort Collins, Colorado.jpg|thumb|Characteristic brick-red tail of Red-tailed Hawk.]] [[File:Red-tailed Hawk, Fort Collins, CO.png|thumb|Red-tailed Hawk, Fort Collins, Colorado]] === Vocalization === The cry of the red-tailed hawk is a 2–3 second, hoarse, rasping scream, variously transcribed as ''kree-eee-ar'', ''tsee-eeee-arrr'' or ''sheeeeee'',<ref name="Avian" /> that begins at a high pitch and slurs downward.<ref name= Ferguson-Lees/><ref name= Brown/><ref name="NY" /> This cry is often described as sounding similar to a steam whistle.<ref name="ADW" /><ref name= Brown/> The red-tailed hawk frequently vocalizes while hunting or soaring, but vocalizes loudest and most persistently in defiance or anger, in response to a predator or a rival hawk's intrusion into its territory.<ref name= Brown/><ref name=Avian/> At close range, it makes a croaking ''guh-runk'', possibly as a warning sound.<ref name="Oregon">{{cite web |title=Red-tailed hawk |department=Birds of prey cards |website=oregonzoo.org |place=Portland, OR |publisher=[[Oregon Zoo]] |url=http://www.oregonzoo.org/Cards/BirdsOfPrey/redtailedhawk.htm |access-date=16 June 2007 |url-status=dead |archive-url=https://web.archive.org/web/20070806054238/http://www.oregonzoo.org/Cards/BirdsOfPrey/redtailedhawk.htm |archive-date=6 August 2007 }}</ref> Nestlings may give peeping notes with a "soft, sleepy quality" that give way to occasional screams as they develop, but those are more likely to be a soft whistle rather than the harsh screams of the adults. Their latter hunger call, given from 11 days (as recorded in Alaska) to after fledgling (in California), is different, a two-syllabled, wailing ''klee-uk'' food cry exerted by the young when parents leave the nest or enter their field of vision.<ref name="Palmer" /><ref name="Hawk Trust">{{cite web |title=Red-tailed Hawk – ''Buteo jamaicensis'' |publisher=[[Hawk Conservancy Trust]] |url=http://www.hawk-conservancy.org/priors/redtail.shtml |access-date=5 June 2007 }}</ref> A strange mechanical sound "not very unlike the rush of distant water" has been reported as uttered in the midst of a sky-dance.<ref name="Palmer" /> A modified call of ''chirp-chwirk'' is given during courtship, while a low key, duck-like nasal ''gank'' may be given by pairs when they are relaxed.<ref name="Brown" /> The fierce, screaming cry of the adult red-tailed hawk is frequently used as a generic [[Bird of prey|raptor]] sound effect in Hollywood movies, television shows and other media, even if the bird featured is not a red-tailed hawk.<ref name=SDZoo>{{cite web |title=Red-Tailed Hawk |series=Animal Bytes |website=sandiegozoo.org/animalbytes |publisher=[[San Diego Zoo]] |url=http://www.sandiegozoo.org/animalbytes/t-red_tailed_hawk.html |access-date=3 March 2012}}</ref><ref>{{cite magazine |title=Raptor porn: The ridiculous proliferation of the red-tail call |date=2013-12-28 |df=dmy-all |magazine=[[Salon (magazine)|Salon]] |url=http://www.salon.com/2013/12/28/raptor_porn_the_ridiculous_proliferation_of_the_red_tail_call/ |url-status=live |archive-url=https://web.archive.org/web/20131228012002/http://www.salon.com/2013/12/28/raptor_porn_the_ridiculous_proliferation_of_the_red_tail_call/ |archive-date=28 December 2013 }}</ref><ref>{{Cite web |title=Hollywood's Voice of Choice |url=https://mdc.mo.gov/blogs/discover-nature-notes/hollywoods-voice-choice-0 |access-date=2025-03-27 |website=Missouri Department of Conservation |language=en}}</ref> It is especially used in depictions of the [[bald eagle]], which contributes to the [[List of common misconceptions#Birds|common misconception]] that it is a bald eagle cry; actual bald eagle vocalizations are far softer and more chirpy than those of a red-tailed hawk.<ref>{{cite news |first=Jessica |last=Robinson |date=2 July 2012 |title=Bald eagle: A mighty symbol, with a not-so-mighty voice |website=npr.org |publisher=[[NPR]] |url=https://www.npr.org/templates/story/story.php?storyId=156187375 |access-date=2019-08-23 |df=dmy-all }}</ref> == Distribution and habitat == [[File:Buteo jamaicensis -Pillar Point Harbor, California, USA-8.jpg|thumb|right|Immature in California]] [[File:Red Tailed Hawk Stare.jpg|thumb|A juvenile red-tailed hawk]] The red-tailed hawk is one of the most widely distributed of all raptors in the Americas. It occupies the largest breeding range of any diurnal raptor north of the Mexican border, just ahead of the [[American kestrel]] (''Falco sparverius''). While the [[peregrine falcon]] (''Falco peregrinus'') has a greater latitudinal distribution as a nester in North America, its range as a breeding species is far more sporadic and sparse than that of red-tailed hawks.<ref name= AOU>American Ornithologists' Union. 1998a. ''Check-list of North American birds. 7th edition ed''. Washington, D.C.: American Ornithologists' Union.</ref> The red-tailed hawk breeds from nearly north-central Alaska, the [[Yukon]], and a considerable portion of the [[Northwest Territories]], there reaching as far as a breeder as [[Inuvik]], [[Mackenzie River]] Delta and skirting the southern shores of [[Great Bear Lake]] and [[Great Slave Lake]]. Thereafter in northern Canada, breeding red-tails continue to northern [[Saskatchewan]] and across to north-central Ontario east to central Quebec and the [[The Maritimes|Maritime Provinces]] of Canada, and south continuously to Florida. No substantial gaps occur throughout the entire contiguous United States where breeding red-tailed hawks do not occur. Along the Pacific, their range includes all of [[Baja California]], including [[Islas Marías]], and [[Socorro Island]] in the [[Revillagigedo Islands]]. On the mainland, breeding red-tails are found continuously to [[Oaxaca]], then experience a brief gap at the [[Isthmus of Tehuantepec]] thereafter subsequently continuing from Chiapas through central Guatemala on to northern Nicaragua. To the south, the population in highlands from Costa Rica to central Panama is isolated from breeding birds in Nicaragua. Further east, breeding red-tailed hawks occur in the [[West Indies]] in north [[Bahamas]] (i.e. [[Grand Bahama]], [[Abaco Islands|Abaco]] and [[Andros, Bahamas|Andros]]) and all larger islands (such as Cuba, Jamaica, Hispaniola, and Puerto Rico) and into the northern [[Lesser Antilles]] ([[Virgin Islands]], [[Saint Barthélemy]], [[Saba (island)|Saba]], [[Saint Kitts]], and [[Nevis]], being rare as a resident on [[Sint Eustatius]] and are probably extinct on [[Saint Martin (island)|Saint Martin]]). Their typical winter range stretches from southern Canada south throughout the remainder of the breeding range.<ref name="Ferguson-Lees" /><ref name="Gov">{{cite web|url=http://www.fs.fed.us/database/feis/animals/bird/buja/all.html#DISTRIBUTION%20AND%20OCCURRENCE|title=''Buteo jamaicensis''|last=Tesky|first=Julie L.|publisher=[[United States Department of Agriculture]]|access-date=10 June 2007}}</ref><ref name="AOU" /> [[File:Red-Tailed Hawk (23367515602).jpg|thumb|left|Red-tailed hawks prefer areas with groves of tall trees from which to hunt and to nest in]] Red-tailed hawks have shown the ability to become habituated to almost any habitat present in North and Central America. Their preferred habitat is mixed forest and [[Meadow|field]], largely [[woodland edge]] with tall [[tree]]s or alternately high [[Cliff|bluffs]] that may be used as nesting and perching sites. They occupy a wide range of habitats and altitudes, including [[desert]]s, [[grassland]]s, nearly any [[coast]]al or [[wetland]] habitat, [[mountain]]s, [[foothill]]s, [[coniferous]] and [[deciduous]] [[woodland]]s, and [[tropical rainforest]]s. [[Agricultural land|Agricultural fields]] and [[pastures]], which are more often than not varied with [[Grove (nature)|grove]]s, ridges, or [[Riparian zone|streamside trees]] in most parts of America, may make nearly ideal habitat for breeding or wintering red-tails. They also adapt well to [[suburban]] areas especially ones with tall trees or any kind of parkland.<ref name=IUCN/><ref name= Palmer/><ref name= Preston/><ref name= Brown/>{{Excessive citations inline|date=April 2023}} Some red-tails may survive or even flourish in urban areas, usually hunting and roosting in available urban [[park]]s, [[cemeteries]], [[road verge]]s, and so on, and nesting freely either in trees or virtually any tall man-made structures.<ref name="Avian">{{cite web|url=http://www.sky-hunters.org/RTHA.pdf |title=Red-tailed Hawk |publisher=Sky-hunters.org |access-date=16 June 2007 |url-status=dead |archive-url=https://web.archive.org/web/20080517111759/http://www.sky-hunters.org/RTHA.pdf |archive-date=17 May 2008 }}</ref><ref>Bildstein, K. L., & Therrien, J. F. (2018). ''Urban birds of prey: a lengthy history of human-raptor cohabitation''. In Urban Raptors (pp. 3–17). Island Press, Washington, DC.</ref> One famous urban red-tailed hawk, known as "[[Pale Male]]", became the subject of a nonfiction book, ''Red-Tails in Love: A Wildlife Drama in Central Park'', and is the first known red-tail in decades to successfully nest and raise young in the crowded New York City borough of [[Manhattan]].<ref>{{cite episode |title=Pale Male – a Red-tailed hawk in New York City |date=May 2004 |series-link=Nature (TV program) |series=Nature |network=[[PBS]] |url=https://www.pbs.org/wnet/nature/episodes/pale-male/introduction/2422/ |access-date=2012-08-22 |df=dmy-all}}</ref><ref name=CBS>{{cite news |last=Geist |first=Bill |title=In love with a hawk |date=10 July 2003 |series=[[CBS News]] |publisher=[[CBS]] |url=https://www.cbsnews.com/news/in-love-with-a-hawk/ }}</ref><ref>{{cite web |title=main |website=Pale Male – the Central Park Red tail hawk (palemale.com) |url=http://www.palemale.com/ |archive-url=https://web.archive.org/web/20111129010335/http://www.palemale.com/ |archive-date=29 November 2011 }}</ref><ref name= Winn>{{cite book |last=Winn |first=M. |year=1999 |title=Red-tails in Love: A wildlife drama in Central Park |place=New York, NY |series=Vintage Departures, Vintage Books |publisher=Random Haouse }}</ref>{{Excessive citations inline|date=April 2023}} As studied in [[Syracuse, New York]], the highway system has been very beneficial to red-tails as it juxtaposed trees and open areas and blocks human encroachment with fences, with the red-tailed hawks easily becoming acclimated to car traffic. The only practice that has a negative effect on the highway-occupying red-tails is the planting of [[Invasive species|exotic]] ''[[Phragmites]]'', which may occasionally obscure otherwise ideal highway habitat.<ref>{{cite journal |last1=Minor |first1=W.F. |last2=Minor |first2=M. |year=1981 |title=Nesting of Red-tailed hawks and Great horned owls in central New York suburban areas |journal= Kingbird |volume=31 |pages= 68–76 |url=https://sora.unm.edu/sites/default/files/journals/jfo/v064n04/p0433-p0439.pdf |via=sora.unm.edu }}</ref> In the northern [[Great Plains]], the widespread practices of [[wildfire suppression]] and planting of exotic trees by humans has allowed groves of [[aspen]] and various other trees to invade what was once vast, almost continuous prairie grasslands, causing grassland obligates such as ferruginous hawks to decline and allowing parkland-favoring red-tails to flourish.<ref name= Palmer/><ref name= Trees>{{cite journal |last=Houston |first=S. |year=1983 |title=Trees and the Red-tailed hawk in southern Saskatchewan |journal= Blue Jay |volume=41|issue=2 |pages=99–109 |doi=10.29173/bluejay4484 |doi-access=free}}</ref> To the contrary, clear-cutting of mature woodlands in [[New England]], resulting in only fragmented and isolated stands of trees or [[Secondary forest|low second growth]] remaining, was recorded to also benefit red-tailed hawks, despite being to the determent of breeding [[red-shouldered hawk]]s.<ref name= Bent>{{cite report |last=Bent |first=A.C. |year=1938 |title=Life histories of North American birds of prey |section=Part 1 |series=[[Bulletin of the United States National Museum]] |volume=170 |pages=295–357 }}</ref> The red-tailed hawk, as a whole, rivals the peregrine falcon and the great horned owl among raptorial birds in the use of diverse habitats in North America.<ref name= Palmer/><ref name=SF>{{cite web | last =Garrigues | first =Jeff | title = Biogeography of Red-tailed hawk |series = Department of Geography | publisher = [[San Francisco State University]] | url =http://bss.sfsu.edu/holzman/courses/Fall00Projects/redtailedhawk.html | url-status =dead | access-date =28 June 2007 | archive-url =https://web.archive.org/web/20071012190407/http://bss.sfsu.edu/holzman/courses/Fall00Projects/redtailedhawk.html | archive-date =12 October 2007}}</ref> Beyond the [[Arctic|high Arctic]] (as they discontinue as a breeder at the tree line), few other areas exist where red-tailed hawks are absent or rare in North and Central America. Some areas of [[Old-growth forest|unbroken forest]], especially lowland tropical forests, rarely host red-tailed hawks, although they can occupy [[Cloud forest|forested tropical highlands]] surprisingly well. In deserts, they can only occur where some variety of [[Semi-arid climate|arborescent growth]] or ample [[Ridge|rocky bluffs]] or [[canyon]]s occur.<ref name=Land>{{cite web |title=Red-tailed Hawk |publisher=U.S. [[Bureau of Land Management]] |url=http://www.blm.gov/pgdata/etc/medialib/blm/id/special_areas/birds_of_prey_nca.Par.63269.File.dat/RedTailedHawk_r.pdf |access-date=12 January 2010}}</ref><ref>{{cite journal |last1=Smith |first1=E.L. |last2=Hoffman |first2=S.W. |last3=Stahlecker |first3=D.W. |last4=Duncan |first4=R.B. |year=1996 |title=Results of a raptor survey in southwestern New Mexico |journal=[[Journal of Raptor Research]] |volume= 30 |issue=4 |pages=183–188 |url=https://sora.unm.edu/node/53555 }}</ref><ref>{{cite journal |last1=Vilella |first1=F.J. |last2=Nimitz |first2=W.F. |year=2012 |title=Spatial Dynamics of the Red-Tailed Hawk in the Luquillo Mountains of Puerto Rico |journal=[[The Wilson Journal of Ornithology]] |volume=124 |issue=4 |pages=758–766 |doi=10.1676/1559-4491-124.4.758 |s2cid=86710442 }}</ref> == Behavior == [[File:Redtail hawk chased by crows 4391.jpg|thumb|left|Red-tailed hawks frequently have to cope with [[Mobbing (animal behavior)|mobbing]] by crows.]] [[File:20250119 red tailed hawk hockanum river linear trail wm2.webm|thumb|left|Red-tailed hawk on a perch, scanning for prey]] The red-tailed hawk is highly conspicuous to humans in much of its daily behavior. Most birds in resident populations, which are well more than half of all red-tailed hawks, usually split nonbreeding-season activity between territorial soaring flight and sitting on a perch. Often, perching is for hunting purposes, but many sit on a tree branch for hours, occasionally stretching on a single wing or leg to keep limber, with no signs of hunting intent.<ref name= Palmer/><ref name= CRPreston/><ref name= Bent/> Wintering typical pale-morph hawks in [[Arkansas]] were found to perch in open areas near the top of tall, isolated trees, whereas dark morphs more frequently perched in dense groups of trees.<ref name= CRPreston/> For many, and perhaps most, red-tailed hawks being [[Mobbing (animal behavior)|mobbed]] by various birds is a daily concern and can effectively disrupt many of their daily behaviors. Mostly larger [[passerine]]s, of multiple families from [[tyrant flycatcher]]s to [[icterid]]s, mob red-tails, despite other raptors, such as ''Accipiter'' hawks and falcons, being a notably greater danger to them.<ref>{{cite journal|author=Knight, R. L., & Temple, S. A. |title=Nest-Defense Behavior in the Red-Winged Blackbird|journal=The Condor|volume=90|issue=1|pages=193–200|url=https://sora.unm.edu/node/103929|doi=10.2307/1368448|jstor=1368448|year=1988|url-access=subscription}}</ref><ref>{{cite journal|author=Chandler, C. R., & Rose, R. K. |year=1988|title=Comparative Analysis of the Effects of Visual and Auditory Stimuli on Avian Mobbing Behavior |url=https://sora.unm.edu/node/51421|journal=Journal of Field Ornithology|pages= 269–277|volume=59|issue=3 }}</ref> The most aggressive and dangerous attacker as such is likely to be various [[crow]]s or other [[corvid]]s, i.e. [[American crow]]s (''Corvus brachyrhynchos''), because a mobbing group (or "murder") of them can number up to as many as 75 crows, which may cause grievous physical harm to a solitary hawk, and if the hawks are nesting, separate the parent hawks and endanger the eggs or nestlings within their nest to predation by crows.<ref>McGowan, K. J. (2001). "Demographic and behavioral comparisons of suburban and rural American Crows". In ''Avian ecology and conservation in an urbanizing world''. Springer US. pp. 365–381. {{ISBN|978-1-4615-1531-9}}</ref><ref>{{cite journal|doi=10.1111/j.1439-0310.1985.tb01375.x|title=Functional interrelationships among the mobbing and alarm caws of Common Crows (''Corvus brachyrhynchos'')|journal=Zeitschrift für Tierpsychologie|volume=67|issue=1–4|pages=17–33|year=2010|last1=Brown|first1=Eleanor D.}}</ref> Birds that mob red-tailed hawks can tell how distended the hawk's crop is (i.e., the upper chest and throat area being puffy versus flat-feathered and sleek), thus mob more often when the hawk is presumably about to hunt.<ref>{{cite journal|author=Hamerstrom, F.|title=The Influence of a Hawk's Appetite on Mobbing|journal=The Condor|volume=59|issue=3|pages=192–194|doi=10.2307/1364723|jstor=1364723|url=https://sora.unm.edu/node/100897|year=1957|url-access=subscription}}</ref> === Flight === [[File:Red-tailed Hawk (Audubon).jpg|thumb|Red-tailed hawks engaging in an inflight battle over prey, painted by [[John James Audubon]]]] In flight, this hawk soars with wings often in a slight [[Dihedral (aeronautics)|dihedral]], flapping as little as possible to conserve energy. Soaring is by far the most efficient method of flight for red-tailed hawks, so is used more often than not.<ref name= Ballam>{{cite journal|author=Ballam, J. M. |year=1984|title=The use of soaring by the Red-tailed Hawk (''Buteo jamaicensis'')|journal=The Auk|pages= 519–524|volume=101|issue=3|url=https://sora.unm.edu/node/23996|jstor=4086604|doi=10.1093/auk/101.3.519|url-access=subscription}}</ref> Active flight is slow and deliberate, with deep wing beats. Wing beats are somewhat less rapid in active flight than in most other ''Buteo'' hawks, even heavier species such as ferruginous hawks tend to flap more swiftly, due to the morphology of the wings.<ref>{{cite journal|pmid=16477604|url=https://pdfs.semanticscholar.org/87ed/457a403bd48158ea835dd08a9a48c3019149.pdf|archive-url=https://web.archive.org/web/20190213123852/https://pdfs.semanticscholar.org/87ed/457a403bd48158ea835dd08a9a48c3019149.pdf|url-status=dead|archive-date=2019-02-13|doi=10.1002/jmor.10425|title=Comparison of wing morphology in three birds of prey: Correlations with differences in flight behavior|journal=Journal of Morphology|volume=267|issue=5|pages=612–622|year=2006|last1=Corvidae|first1=Elaine L.|last2=Bierregaard|first2=Richard O.|last3=Peters|first3=Susan E.|s2cid=2484938}}</ref> In wind, it occasionally hovers on beating wings and remains stationary above the ground, but this flight method is rarely employed by this species.<ref name="Preston" /><ref name="Land" /> When soaring or flapping its wings, it typically travels from {{convert|32|to|64|km/h|mi/h|abbr=on}}, but when diving may exceed {{convert|190|km/h|mi/h|abbr=on}}.<ref name="NY">{{cite web|url=http://www.nysite.com/nature/fauna/redhawk.htm|archive-url=https://archive.today/19970627092314/http://www.nysite.com/nature/fauna/redhawk.htm|url-status=dead|archive-date=27 June 1997|author=Day, Leslie|publisher=[[79th Street Boat Basin]] Flora and Fauna Society|title=The City Naturalist – Red Tailed Hawk|access-date=17 June 2007}}</ref> Although North American red-tailed hawks will occasionally hunt from flight, a great majority of flight by red-tails in this area is for non-hunting purpose.<ref name="Ballam" /> During nest defense, red-tailed hawks may be capable of surprisingly swift, vigorous flight, while repeatedly diving at perceived threats.<ref name="Knight">{{cite journal|author=Knight, R. L., Andersen, D. E., Bechard, M. J., & Marr, N. V.|title=Geographic variation in nest-defence behaviour of the Red-tailed Hawk ''Buteo jamaicensis''|journal=Ibis|volume=131|pages=22–26|url=http://globalraptors.org/grin/researchers/uploads/529/geographic_variation_knight_et_al..pdf|doi=10.1111/j.1474-919X.1989.tb02739.x|year=2008|access-date=13 February 2019|archive-date=8 August 2017|archive-url=https://web.archive.org/web/20170808225104/http://www.globalraptors.org/grin/researchers/uploads/529/geographic_variation_knight_et_al..pdf|url-status=dead}}</ref> ===Migration=== Red-tailed hawks are considered partial migrants, as in about the northern third of their distribution, which is most of their range in Canada and Alaska, they almost entirely vacate their breeding grounds.<ref name= Ferguson-Lees/><ref name= Preston/> In coastal areas of the north, however, such as in the [[Pacific Northwest]] to southern Alaska and in [[Nova Scotia]] on the Atlantic, red-tailed hawks do not usually migrate.<ref name= Palmer/> More or less, any area where snow cover is nearly continuous during the winter shows an extended absence of most red-tailed hawks, so some areas as far south as Montana may show strong seasonal vacancies of red-tails.<ref name= Palmer/> In southern Michigan, immature red-tailed hawks tended to remain in winter only when voles were abundant. During relatively long, harsh winters in Michigan, many more young ones were reported in northeastern Mexico.<ref name="Palmer" /><ref name="Craighead" /> To the opposite extreme, hawks residing as far north as [[Fairbanks]], Alaska, may persevere through the winter on their home territory, as was recorded with one male over three consecutive years.<ref name="Lowe">Lowe, C. 1978. ''Certain life history aspects of the Red-tailed Hawk, central Oklahoma and interior Alaska''. Master's Thesis, Univ. Alaska, Fairbanks.</ref> Birds of any age tend to be territorial during winter but may shift ranges whenever food requirements demand it.<ref name="Palmer" /> Wintering birds tend to perch on inconspicuous tree perches, seeking shelter especially if they have a full crop or are in the midst of poor or overly windy weather. Adult wintering red-tails tend to perch more prominently than immatures do, which select lower or more secluded perches. Immatures are often missed in winter bird counts, unless they are being displaced by dominant adults. Generally, though, immatures can seem to recognize that they are less likely to be attacked by adults during winter and can perch surprisingly close to them. Age is the most significant consideration of wintering hawks' hierarchy, but size does factor in, as larger immatures (presumably usually females) are less likely to displaced than smaller ones.<ref name="CRPreston" /><ref name="Palmer" /><ref name="Preston" /> Dark adult red-tailed hawks appear to be harder to locate when perched than other red-tails. In Oklahoma, for example, wintering adult Harlan's hawks were rarely engaged in fights or chased by other red-tails. These hawks tended to gather in regional pockets and frequently the same ones occurred year-to-year.<ref name="Lowe" /> In general, migratory behavior is complex and reliant on each individual hawk's decision-making (i.e. whether prey populations are sufficient to entice the hawk to endure prolonged snow cover).<ref name="Preston" /> During fall migration, departure may occur as soon as late September, but peak movements occur in late October and all of November in the United States, with migration ceasing after mid-December. The northernmost migrants may pass over resident red-tailed hawks in the contiguous United States, while the latter are still in the midst of brooding fledglings.<ref name="Palmer" /> Not infrequently, several autumn hawk watches in Ontario, Quebec, and the northern United States record 4,500–8,900 red-tailed hawks migrating through each fall, with records of up to 15,000 in a season at Hawk Ridge hawk watch in [[Duluth, Minnesota]].<ref name="Ferguson-Lees" /><ref>{{cite journal|author=Farmer, C. J., Bell, R. J., Drolet, B., Goodrich, L. J., Greenstone, E., Grove, D., & Sodergren, J. |year=2008|url=http://www.rpi-project.org/publications/TP-08.pdf |title=Trends in autumn counts of migratory raptors in northeastern North America, 1974–2004|journal= Series in Ornithology|volume=3|pages=179–215}}</ref> Unlike some other ''Buteo'' spp., such as Swainson's hawks and broad-winged hawks, red-tailed hawks do not usually migrate in groups, instead passing by one-by-one, and only migrate on days when winds are favorable.<ref name="Ferguson-Lees" /><ref name="Palmer" /> Most migrants do not move past southern Mexico in late autumn, but a few North American migrants may annually move as far south as breeding red-tailed hawks happen to occur, i.e. in Central America to as far south Panama. However, a few records were reported of wintering migrant red-tails turning up in [[Colombia]], the first records of them anywhere in South America.<ref name="Ferguson-Lees" /><ref name="Preston" /><ref>{{cite journal|author=Castaño R, A. M. & Colorado G.J. |year=2002|title=First records of red-tailed hawk ''Buteo jamaicensis'' in Colombia|journal=Cotinga |volume= 18|pages= 102}}</ref> Spring northward movements may commence as early as late February, with peak numbers usually occurring in late March and early April. Seasonal counts may include up to 19,000 red-tails in spring at Derby Hill hawk watch, in [[Oswego, New York]], sometimes more than 5,000 are recorded in a day there.<ref name="Ferguson-Lees" /><ref>{{cite journal|author=Haugh, J. R., & Cade, T. J. |year=1966|title=The spring hawk migration around the southeastern shore of Lake Ontario|journal= The Wilson Bulletin|volume=78|issue=1 |pages= 88–110|jstor=4159454|url=https://sora.unm.edu/node/128271}}</ref> The most northerly migratory individuals may not reach breeding grounds until June, even adults.<ref name="Ferguson-Lees" /><ref name="Lowe" /> Immature hawks migrate later than adults in spring on average, but not, generally speaking, in autumn. In the northern Great Lakes, immatures return in late May to early June, when adults are already well into their nesting season and must find unoccupied ranges.<ref name= Palmer/> In Alaska, adults tend to migrate before immatures in early to mid-September, to the contrary of other areas, probably as heavy snowfall begins.<ref name= Lowe/><ref>{{cite journal|author=Luttich, S. N., L. B. Keith and J. D. Stephenson|year= 1971|title=Population dynamics of the Red-tailed Hawk (''Buteo jamaicensis'') at Rochester, Alberta|journal= Auk |issue=1|volume= 88|pages=75–87|url=https://sora.unm.edu/node/22072|doi= 10.2307/4083962|jstor= 4083962|doi-access=free}}</ref> Yearlings that were banded in southwestern [[Idaho]] stayed for about 2 months after fledging, and then traveled long distances with a strong directional bias, with 9 of 12 recovered southeast of the study area- six of these moved south to coastal lowlands in Mexico] and as far as Guatemala, {{convert|4205|km|mi|abbr=on}} from their initial banding.<ref>{{cite journal|author=Steenhof, K., Kochert, M. N., & Moritsch, M. Q. |year=1984|title=Dispersal and migration of southwestern Idaho raptors|journal= Journal of Field Ornithology|jstor=4512919 |volume= 55|issue=3|pages= 357–368|url=https://sora.unm.edu/node/51120}}</ref> In California, 35 hawks were banded as nestlings; 26 were recovered at less than 50 miles away, with multidirectional juvenile dispersals. Nestlings banded in Southern California sometimes actually traveled north as far as {{convert|1190|km|mi|abbr=on}} to Oregon, ranging to the opposite extreme as far as a banded bird from the [[Sierra Nevada]]s that moved {{convert|1700|km|mi|abbr=on}} south to [[Sinaloa]].<ref name= Palmer/><ref>{{cite journal|author=Hoffman, S. W., Smith, J. P., & Meehan, T. D. |year=2002|title=Breeding grounds, winter ranges, and migratory routes of raptors in the Mountain West|url=https://sora.unm.edu/node/53957 |journal=Journal of Raptor Research|volume= 36|issue=2|pages= 97–110}}</ref> Nestlings banded in [[Green County, Wisconsin]], did not travel very far comparatively by October–November, but by December, recoveries were found in states including Illinois, Iowa, Texas, Louisiana, and Florida.<ref name= Orians>{{cite journal|doi=10.2307/1365056 |jstor=1365056|url=https://sora.unm.edu/node/100838|title=Red-Tailed Hawk and Horned Owl Populations in Wisconsin|journal=The Condor|volume=58|issue=5|pages=371–385|year=1956|last1=Orians|first1=Gordon|last2=Kuhlman|first2=Frank|url-access=subscription}}</ref> == Diet== [[File:JuveRTH%2BRat.png|thumb|left|Juvenile eating a [[brown rat]]]] {{too much detail|section|date=August 2024}} The red-tailed hawk is [[carnivorous]] and a highly opportunistic feeder. Nearly any small animal they encounter may be viewed as potential food.<ref name= CRPreston/> Their most common prey are small mammals such as [[rodent]]s and [[lagomorph]]s, but they also consume birds, reptiles, fish, [[amphibian]]s, and [[invertebrate]]s. Prey varies considerably with regional and seasonal availability, but usually centers on rodents, accounting for up to 85% of a hawk's diet.<ref name="ADW" /> In total, nearly 500 prey species have been recorded in their diet, almost as many as great horned owls have been recorded as taking.<ref name= Preston/><ref name= Bent/><ref name= Sherrod>{{cite journal|author=Sherrod, S. K. |year=1978|title=Diets of North American Falconiformes|journal=Raptor Res|volume= 12|issue=3/4|pages=49–121|url=https://sora.unm.edu/node/52680}}</ref><ref name= Blumstein>Blumstein, D.T. (1986). [https://blumsteinlab.eeb.ucla.edu/wp-content/uploads/sites/104/2017/05/Blumstein_1986.pdf ''The Diets and Breeding Biology of Red-tailed Hawks in Boulder County: 1985 Nesting Season'']. Colorado Division of Wildlife.</ref> When 27 North American studies are reviewed, mammals make up 65.3% of the diet by frequency, 20.9% by birds, 10.8% by reptiles, 2.8% by invertebrates, and 0.2% by amphibians and fish.<ref name= Palmer/><ref name= CRPreston/><ref name= Sherrod/><ref name= Blumstein/> The geometric mean body mass of prey taken by red-tailed hawks in North America is about {{convert|187|g|oz|abbr=on}} based on a pair of compilation studies from across the continent, regionally varying at least from {{convert|43.4|to|361.4|g|oz|abbr=on}}.<ref>{{cite journal|doi=10.1139/z83-295|title=Food-niche relationships and guild structure of diurnal birds of prey: Competition versus opportunism|url=https://archive.org/details/sim_canadian-journal-of-zoology_1983-10_61_10/page/2230|journal=Canadian Journal of Zoology|volume=61|issue=10|pages=2230–2241|year=1983|last1=Jaksić|first1=Fabian M.|last2=Braker|first2=H. Elizabeth|bibcode=1983CaJZ...61.2230J }}</ref><ref name= Marti95>{{cite journal |first1=Carl D. |last1=Marti |first2=Michael N. |last2=Kochert |year=1995 |title=Are Red-tailed Hawks and Great Horned Owls diurnal–nocturnal dietary counterparts? |journal=[[Wilson Bulletin]] |volume=107 |issue=4 |pages=615–628 |url=https://sora.unm.edu/node/131328 |jstor=4163598 |access-date=13 February 2019 |archive-date=6 March 2021 |archive-url=https://web.archive.org/web/20210306185023/https://sora.unm.edu/node/131328 |url-status=dead }}</ref> Staple prey (excluding invertebrates) has been claimed to weigh from {{convert|15|to|2114|g|lb|abbr=on}}, ranging roughly from the size of a small mouse or lizard to the size of a [[black-tailed jackrabbit]] (''Lepus californicus'').<ref name= Palmer/><ref name= Preston/><ref name= Steenhof2>{{cite journal|pmid=28310806|doi=10.1007/BF00378546|title=Dietary shifts of sympatric buteos during a prey decline|url=https://archive.org/details/sim_oecologia_1985-04_66_1/page/6|journal=Oecologia|volume=66|issue=1|pages=6–16|year=1985|last1=Steenhof|first1=K.|last2=Kochert|first2=M. N.|bibcode=1985Oecol..66....6S|s2cid=1726706}}</ref> The daily food requirements range from 7 to 11.2% of their own body weight, so that about three [[vole]]s or the equivalent weight are required daily for a typical range adult.<ref name= Craighead/> [[File:Red-tailed hawk claw avalon mid march (14254392156).jpg|thumb|right|Formidable feet and talons of a red-tailed hawk.]] The talons and feet of red-tailed hawks are relatively large for a ''Buteo'' hawk; in an average-sized adult red-tail, the "hallux-claw" or rear talon, the largest claw on all accipitrids, averages about {{convert|29.7|mm|in|abbr=on}}.<ref name= Pearlstine/><ref>{{cite journal|pmid=28097061|pmc=5228515|title=Contrasting molecular and morphological evidence for the identification of an anomalous ''Buteo'': a cautionary tale for hybrid diagnosis|journal=PeerJ|volume=5|pages=e2850|year=2017|last1=Clark|first1=W. S.|last2=Galen|first2=S. C.|last3=Hull|first3=J. M.|last4=Mayo|first4=M. A.|last5=Witt|first5=C. C.|doi=10.7717/peerj.2850 |doi-access=free }}</ref> In fact, the talons of red-tails in some areas averaged of similar size to those of ferruginous hawks which can be considerably heavier and notably larger than those of the only slightly lighter Swainson's hawk.<ref name= Pearlstine/><ref name= Restani>{{cite journal|author=Restani, M. |title=Resource Partitioning among Three ''Buteo'' Species in the Centennial Valley, Montana|url=https://archive.org/details/sim_condor_1991-11_93_4/page/1007 |journal=The Condor|volume=93|issue=4|pages=1007–1010|doi=10.2307/3247736|jstor=3247736|year=1991}}</ref><ref>{{cite journal|author=Sarasola, J. H., & Negro, J. J. |year=2004|title=Gender determination in the Swainson's Hawk (''Buteo swainsoni'') using molecular procedures and discriminant function analysis|url=https://sora.unm.edu/node/54136|journal= Journal of Raptor Research|volume= 38|issue=4|pages=357–361}}</ref> This species may exert an average of about {{convert|91|kg/cm2|lb/in2|abbr=on}} of pressure through its feet.<ref name= Pearlstine/><ref>{{cite journal|pmid=19946365|pmc=2776979|year=2009|last1=Fowler|first1=D. W.|title=Predatory functional morphology in raptors: Interdigital variation in talon size is related to prey restraint and immobilisation technique|journal=PLOS ONE|volume=4|issue=11|pages=e7999|last2=Freedman|first2=E. A.|last3=Scannella|first3=J. B.|doi=10.1371/journal.pone.0007999|bibcode=2009PLoSO...4.7999F|doi-access=free}}</ref><ref name= Goslow>{{cite journal|author=Goslow, G. E. |url=https://sora.unm.edu/node/22175|year=1971|title=The attack and strike of some North American raptors|journal=The Auk|pages= 815–827|volume=88|issue=4|doi=10.2307/4083840|jstor=4083840|doi-access=free}}</ref> Owing to its morphology, red-tailed hawks generally can attack larger prey than other ''Buteo'' hawks typically can, and are capable of selecting the largest prey of up to their own size available at the time of hunting, though in all likelihood numerically most prey probably weighs on average about 20% of the hawk's own weight (as is typical of many birds of prey).<ref name= Preston/><ref name= Craighead/><ref name= Marti93>Marti, C. D., Korpimäki, E., & Jaksić, F. M. (1993). ''Trophic structure of raptor communities: a three-continent comparison and synthesis''. In Current ornithology (pp. 47–137). Springer US.</ref> Red-tailed hawks usually hunt by watching for prey activity from a high perch (also known as still hunting), from which they drop down upon by the prey. Red-tails often select the highest available perches to decrease wing flapping and increase the downward glide during an attack. Perch hunting is the most successful hunting method for red-tailed hawks and can account for up to 83% of their daily activities in the winter.<ref name= Preston/><ref name= Palmer/><ref>{{cite journal|author=Orde, C. J., & Harrell, B. E. |year=1977|title=Hunting techniques and predatory efficiency of nesting Red-tailed Hawks|journal=Journal of Raptor Research|volume= 11|pages= 82–85|url=https://sora.unm.edu/node/52665 }}</ref> Pairs may [[Pack hunter|join]] to hunt agile prey that they may have trouble catching by themselves, such as [[tree squirrel]]s. This may consist of stalking opposites sides of a tree to surround the squirrel and drive the rodent to a hawk.<ref name= Palmer/><ref name= Brown/> [[File:Red-tailed Hawk (Buteo jamaicensis) -diving.jpg|thumb|right|The typical hunting method of red-tailed hawks is to dive down on its prey from a lofty perch.]] [[File:Red-tailed Hawk imported from iNaturalist photo 348570364 on 5 December 2024.jpg|thumb|Coughing up a [[Pellet (ornithology)|pellet]]]] The most common flighted hunting method for the red-tail is to cruise around {{convert|10|to|50|m|ft|abbr=on}} over the ground with flap-and-glide type flight, interspersed occasionally with [[Harrier (bird)|harrier]]-like quarters over the ground. This method is less successful than perch hunting but seems relatively useful for capturing small birds and may show the best results over hilly country.<ref name= Ferguson-Lees/><ref name= Palmer/><ref name= Brown/> Red-tailed hawks readily use trees, bushes, or rocks for concealment before making a surprise attack, even showing a partial ability to dodge among trees in an ''Accipiter''-like fashion. Among thick stands of [[spruce]] in Alaska, a dodging hunting flight was thought to be unusually important to red-tails living in extensive areas of conifers, with hawks even coming to the ground and walking hurriedly in prey pursuit especially if the prey was large, a similar behavior to [[American goshawk|goshawks]].<ref name= Palmer/><ref name= Lowe/> In Texas, swift aerial hunting has been reported in red-tails that habitually hunt bats. The hawks stooped with half-closed wings, quite falcon-like, plowing through the huge stream of bats exiting their cave roosts, then zooming upwards with bats in their talons. The hawks were also seen flying closely to the stream of bats, then veering sharply into it to seize a bat.<ref name="Lee">{{cite journal|author=Lee, Y. F., & Kuo, Y. M. |year=2001|title=Predation on Mexican free-tailed bats by peregrine falcons and red-tailed hawks|journal=Journal of Raptor Research|volume= 35|issue=2|pages= 115–123|url=https://sora.unm.edu/node/53877}}</ref><ref name="Twente">{{cite journal|author=Twente, J. W. |year=1954|jstor=4158291|title=Predation on bats by hawks and owls|journal=The Wilson Bulletin|volume= 66|issue=2|pages= 135–136|url=https://sora.unm.edu/node/127345}}</ref><ref>{{cite journal|author=Mikula, P., Morelli, F., Lučan, R. K., Jones, D. N., & Tryjanowski, P. |year=2016|title=Bats as prey of diurnal birds: a global perspective|journal=Mammal Review|volume=46|issue=3|pages=160–174|doi=10.1111/mam.12060|bibcode=2016MamRv..46..160M }}</ref> In the [[neotropics]], red-tails have shown the ability to dodge among forest canopy while hunting.<ref name="Ferguson-Lees" /><ref name="Santana">{{cite journal|author=Santana, E., & Temple, S. A.|year=1988|title=Breeding Biology and Diet of Red-Tailed Hawks in Puerto Rico|journal=Biotropica|volume=20|issue=2|pages=151–160|doi=10.2307/2388188|jstor=2388188|bibcode=1988Biotr..20..151C }}</ref> In [[Kansas]], red-tailed hawks were recorded sailing to catch flying insects, a hunting method more typical of a Swainson's hawk.<ref>Goss, N. S. (1891). ''History of the Birds of Kansas''. Geo. W. Crane and Co., Topeka, Kansas.</ref> Alternately, they may drop to the ground to forage for insects like [[grasshopper]]s and [[beetle]]s as well as other invertebrates and probably amphibians and fish (except by water in the latter cases). Hunting afoot seems to be particularly prevalent among immatures. Young red-tailed hawks in northeastern Florida were recorded often extracting [[earthworm]]s from near the surface of the ground and some had a crop full of earthworms after rains. Ground hunting is also quite common on [[Socorro Island]], where no native land mammals occur, and invertebrates are more significant to their overall diet.<ref name="Ferguson-Lees" /><ref name="Palmer" /><ref>{{cite journal|author=Jehl, J. R., & Parkes, K. C. |year=1982|url=https://sora.unm.edu/node/129891|title=The status of the avifauna of the Revillagigedo Islands, Mexico|jstor=4161573|journal=Wilson Bull|volume= 94|issue=1|pages=1–19}}</ref> A red-tailed hawk was observed to incorporate an unconventional killing method, which was drowning a [[Yellow-crowned night heron|heron]] immediately after capture.<ref>{{cite journal|author=Richter R. |year=1985|title=Red-tailed Hawk drowns Yellow-crowned Night Heron|journal=Florida Field Naturalist|volume= 13|pages= 12–13|url=https://sora.unm.edu/node/134066}}</ref> Upon capture, smaller prey is taken to a feeding perch, which is almost always lower than a hunting perch. Among small prey, rodents are often swallowed whole, as are [[shrew]]s and small snakes, while birds are plucked and beheaded. Even prey as small as [[chipmunk]]s may take two or three bites to consume. Larger mammals of transportable size are at times beheaded and have part of their fur discarded. Leftovers are either stored in a tree or fall to the ground. Large prey, especially if too heavy to transport on the wing, is often dragged to a secluded spot and dismantled in various ways. If they can successfully carry what remains to a low perch, red-tails tend to feed until full and then discard the rest.<ref name="Palmer" /><ref name="CRPreston" /><ref name="Brown" /> ===Mammals=== [[File:Red-tailed Hawk Eating a Rodent 1080p 60fps.ogv|thumb|thumbtime=12|Red-tailed hawk eating a rodent]] [[File:20250101 red tailed hawk dines on squirrel hockanum reservoir.webm|thumb|Eating the remains of an [[Eastern Gray Squirrel]]]] Rodents are certainly the type of prey taken most often by frequency, but their contribution to prey biomass at nests can be regionally low, and the type, variety, and importance of rodent prey can be highly variable. In total, well over 100 rodent species have turned up the diet of red-tailed hawks.<ref name= Preston/><ref name= Sherrod/><ref name= Blumstein/> Rodents of extremely varied sizes may be hunted by red-tails, with species ranging in size from the {{convert|8.2|g|oz|abbr=on}} [[eastern harvest mouse]] (''Reithrodontomys humulis'') to full grown [[muskrat]]s (''Ondatra zibethicus'').<ref>Turner, Ashley S., L. Mike Conner, and Robert J. Cooper. "Supplemental feeding of northern bobwhite affects red‐tailed hawk spatial distribution." The Journal of Wildlife Management 72.2 (2008): 428–432.</ref><ref>{{cite journal|author=Stalling, D. T. |year=1997|title=''Reithrodontomys humulis''|journal= Mammalian Species|issue=565|pages=1–6|doi=10.2307/3504466|jstor=3504466|doi-access=free}}</ref><ref name= Bare>{{cite journal|author=Fitch, H. S., & Bare, R. O. |year=1978|title=A field study of the Red-tailed Hawk in eastern Kansas|journal=Transactions of the Kansas Academy of Science|volume=81|issue=1|pages= 1–13|jstor=3627354|doi=10.2307/3627354}}</ref><ref>Fisher, Albert Kenrick. The hawks and owls of the United States in their relation to agriculture. No. 3. US Department of Agriculture, Division of Ornithology and Mammalogy, 1893.</ref> At times, the red-tailed hawk is thought of as a semi-specialized [[vole]]-catcher, but voles are a subsistence food that is more or less taken until larger prey such as rabbits and squirrels can be captured. In an area of [[Michigan]], immature hawks took almost entirely voles but adults were diversified feeders.<ref name= Palmer/><ref name= Craighead/> Indeed, the {{convert|44.1|g|oz|abbr=on}} [[meadow vole]] (''Microtus pennsylvanicus'') was the highest frequency prey species in 27 dietary studies across North America, accounting for up to 54% of the food at nests by frequency. It is quite rare for any one species to make up more than half of the food in any dietary study for red-tailed hawks.<ref name="Palmer" /><ref name="CRPreston" /><ref name="Sherrod" /><ref name="Blumstein" /><ref>{{cite journal|author=Reich, L. M. |year=1981|title=''Microtus pennsylvanicus''|journal= Mammalian Species|issue=159|pages= 1–8|doi=10.2307/3503976|jstor=3503976|s2cid=253949975 |doi-access=free}}</ref><ref>{{cite journal|author=English, P. F. |year=1934|title=Some observations on a pair of Red-tailed Hawks|journal=The Wilson Bulletin|volume= 46|issue=4|pages=228–235|jstor=4156331|url=https://sora.unm.edu/node/125807}}</ref> In total about 9 ''[[Microtus]]'' species are known in the overall diet, with 5 other voles and [[lemming]]s known to be included in their prey spectrum.<ref name="Sherrod" /><ref name="Blumstein" /> Another well-represented species was the {{convert|27.9|g|oz|abbr=on}} [[prairie vole]] (''Microtus ochrogaster''), which were the primary food, making up 26.4% of a sample of 1322, in eastern [[Kansas]].<ref name="Bare" /> While [[crepuscular]] in primary feeding activity, voles are known to be active both day and night, and so are reliable food for hawks than most non-squirrel rodents, which generally are nocturnal in activity.<ref name="Craighead" /><ref>{{cite journal|doi=10.3758/BF03199612|title=Diurnal patterning of eight activities in 14 species of muroid rodents|journal=Animal Learning & Behavior|volume=8|issue=2|pages=322–330|year=1980|last1=Baumgardner|first1=Denis J.|last2=Ward|first2=Susan E.|last3=Dewsbury|first3=Donald A.|doi-access=free}}</ref><ref>{{cite journal|author=Dark, J., & Zucker, I. |title=Short photoperiods reduce winter energy requirements of the meadow vole, ''Microtus pennsylvanicus''|journal=Physiology & Behavior|volume=31|issue=5|pages=699–702|pmid=6364189|year=1983|doi=10.1016/S0031-9384(83)80006-7|s2cid=26871857}}</ref> Indeed, most other [[Cricetidae|microtine rodents]] are largely inaccessible to red-tailed hawks due to their strongly nocturnal foraging patterns, even though 24 species outside of voles and lemmings are known to be hunted. [[Woodrat]]s are taken as important supplemental prey in some regions, being considerably larger than most other crictetid rodents, and some numbers of [[North American deermouse]] (''Peromyscus maniculatus'') may turn up. The largest representation of the latter species was contributing 11.9% of the diet in the [[Great Basin]] of [[Utah]], making them the second best-represented prey species there.<ref name="Sherrod" /><ref name="Smith"> {{cite journal|author=Smith, D. G., & Murphy, J. R. |year=1973|title=Breeding ecology of raptors in the eastern Great Basin of Utah|journal=Brigham Young University Science Bulletin, Biological Series|volume= 18|issue=3|url=https://scholarsarchive.byu.edu/byuscib/vol18/iss3/1}}</ref> Considering this limited association with nocturnal rodents, the high importance of [[pocket gopher]]s in the diet of red-tailed hawks is puzzling to many biologists, as these tend to be highly nocturnal and elusive by day, rarely leaving the confines of their burrow. At least 8 species of pocket gopher are included in the prey spectrum (not to mention 5 species of [[pocket mice]]). The {{convert|110|g|oz|abbr=on}} [[northern pocket gopher]] (''Thomomys talpoides'') is particularly often reported and, by frequency, even turns up as the third most often recorded prey species in 27 American dietary studies. Presumably, hunting of pocket gophers by red-tails, which has possibly never been witnessed, occurs in dim light at first dawn and last light of dusk when they luck upon a gopher out foraging.<ref name="Palmer" /><ref name="Sherrod" /><ref name="Blumstein" /><ref> {{cite journal|author=Verts, B. J., & Carraway, L. N. |year=1999|title= ''Thomomys talpoides''|journal= Mammalian Species|issue=618|pages= 1–11|doi=10.2307/3504451|jstor=3504451|doi-access=free}}</ref><ref> {{cite journal|author=Howard, W., & Childs, H. |year=1959|title=Ecology of pocket gophers with emphasis on ''Thomomys bottae mewa''|journal=Hilgardia|volume=29|issue=7|pages=277–358|doi=10.3733/hilg.v29n07p277|doi-access=free}}</ref> [[File:Hawk eating prey edit.jpg|thumb|left|Voles are often caught by red-tails, especially immature hawks such as this may depend almost fully upon them.]] By far, the most important prey among rodents is [[squirrel]]s, as they are almost fully diurnal. All told, nearly 50 species from the squirrel family have turned up as food. In particular, where they are distributed, [[ground squirrel]]s are doubly attractive as a primary food source due to their ground-dwelling habits, as red-tails prefer to attack prey that is terrestrial.<ref name= Preston/><ref name= Palmer/><ref name= Sherrod/><ref name= Blumstein/> There are also many disadvantages to ground squirrels as prey: they can escape quickly to the security of their burrows, they tend to be highly social and they are very effective and fast in response to alarm calls, and a good deal of species enter [[hibernation]] that in the coldest climates can range up to a 6 to 9-month period (although those in warmer climates with little to no snowy weather often have brief dormancy and no true hibernation). Nonetheless, red-tailed hawks are devoted predators of ground squirrels, especially catching incautious ones as they go out foraging (which are often younger animals).<ref> {{cite journal|author=Armitage, K. B. |title=Sociality as a life-history tactic of ground squirrels|url=https://archive.org/details/sim_oecologia_1981-02_48_1/page/36 |journal=Oecologia|volume=48|issue=1|pages=36–49|pmid=28309931|year=1981|doi=10.1007/BF00346986|bibcode=1981Oecol..48...36A|s2cid=31942417}}</ref><ref>{{cite journal|author=Daan, S., Barnes, B. M., & Strijkstra, A. M.|title=Warming up for sleep? Ground squirrels sleep during arousals from hibernation|journal=Neuroscience Letters|volume=128|issue=2|pages=265–8|pmid=1945046|year=1991|doi=10.1016/0304-3940(91)90276-Y|s2cid=13802495|url=https://www.rug.nl/research/portal/en/publications/warming-up-for-sleep--ground-squirrels-sleep-during-arousals-from-hibernation(a2c377a6-7cf9-4fd1-bebd-5cca8583762a).html|access-date=6 December 2019|archive-date=28 September 2020|archive-url=https://web.archive.org/web/20200928004231/https://www.rug.nl/research/portal/en/publications/warming-up-for-sleep--ground-squirrels-sleep-during-arousals-from-hibernation(a2c377a6-7cf9-4fd1-bebd-5cca8583762a).html|url-status=dead|url-access=subscription}}</ref><ref> {{cite journal|author=Owings, D. H., Borchert, M., & Virginia, R. |title=The behaviour of California ground squirrels|url=https://archive.org/details/sim_animal-behaviour_1977-02_25_1/page/221 |journal=Animal Behaviour|volume=25|pages=221–230|doi=10.1016/0003-3472(77)90085-9|year=1977|s2cid=53158532}}</ref><ref> {{cite journal|author=Wilson, D. R., & Hare, J. F. |title=Animal communication: Ground squirrel uses ultrasonic alarms|journal=Nature|volume=430|issue=6999|pages=523|pmid=15282596|year=2004|doi=10.1038/430523a|bibcode=2004Natur.430..523W|s2cid=4348026|url=http://research.library.mun.ca/9771/1/2004_Wilson_%26_Hare_2004_Nature.pdf}}</ref> A multi-year study conducted on [[San Joaquin Experimental Range]] in California, seemingly still the largest food study to date done for red-tailed hawks with 4031 items examined, showed that throughout the seasons the {{convert|722|g|lb|abbr=on}} [[California ground squirrel]] (''Otospermophilus beecheyi'') was the most significant prey, accounting for 60.8% of the breeding season diet and about 27.2% of the diet for hawks year-around. Because of the extremely high density of red-tailed hawks on this range, some pairs came to specialize in diverse alternate prey, which consisted variously of [[kangaroo rat]]s, [[lizard]]s, snakes or [[chipmunk]]s. One pair apparently lessened competition by focusing on [[pocket gopher]]s instead despite being near the center of ground squirrel activity.<ref name="Fitch"> {{cite journal|doi=10.2307/1363939|author=Fitch, H. S., Swenson, F., & Tillotson, D. F. |title=Behavior and food habits of the Red-tailed Hawk|url=https://sora.unm.edu/node/99748|journal=The Condor|volume= 48|issue=5|pages= 205–237|jstor=1363939 |year=1946 }}</ref><ref> {{cite journal|author=Tromborg, C. T., & Coss, R. G. |title=Isolation rearing reveals latent antisnake behavior in California ground squirrels (''Otospermophilus becheeyi'') searching for predatory threats|journal=Animal Cognition|volume=18|issue=4|pages=855–65|pmid=25726178|year=2015|doi=10.1007/s10071-015-0853-5|s2cid=17594129|url=https://escholarship.org/content/qt3gj370jd/qt3gj370jd.pdf?t=o196y3}}</ref> In [[Morley Nelson Snake River Birds of Prey National Conservation Area|Snake River NCA]], the primary food of red-tailed hawks was the {{convert|203.5|g|oz|abbr=on}} [[Townsend's ground squirrel]] (''Urocitellus townsendii''), which made up nearly 21% of the food in 382 prey items across several years despite sharp spikes and crashes of the ground squirrel population there.<ref name="Steenhof2" /><ref> {{cite journal|author=Rickart, E. A. |year=1987|title= ''Spermophilus townsendii''|journal= Mammalian Species|volume=268|pages= 1–6|doi=10.2307/0.268.1|doi-access=free}}</ref> The same species was the main food of red-tailed hawks in southeastern [[Washington (state)|Washington]], making up 31.2% of 170 items.<ref name="Fitzner">Fitzner, R. E., Rickard, W. H., Cadwell, L. L., & Rogers, L. E. (1981). ''Raptors of the Hanford site and nearby areas of southcentral Washington (No. PNL-3212)''. Battelle Pacific Northwest Labs., Richland, WA (USA).</ref> An even closer predatory relationship was reported in the [[Centennial Mountains|Centennial valley]] of [[Montana]] and south-central Montana, where 45.4% of 194 prey items and 40.2% of 261 items, respectively, of the food of red-tails consisted of the {{convert|455.7|g|lb|abbr=on}} [[Richardson's ground squirrel]] (''Urocitellus richardsonii'').<ref name="Restani" /><ref name="Seidensticker"> {{cite journal|author=Seidensticker, J. C. |year=1970|title=Food of nesting Red-tailed Hawks in south-central Montana|journal= The Murrelet|volume= 51|issue=3|pages=38–40|doi=10.2307/3534043|jstor=3534043}}</ref><ref> {{cite journal|author=Michener, G. R., & Koeppl, J. W. |year=1985|title=''Spermophilus richardsonii''|journal= Mammalian Species|issue=243|pages= 1–6|doi=10.2307/3503990|jstor=3503990|doi-access=free}}</ref> Locally in [[Rochester, Alberta]], [[Richardson's ground squirrel]], estimated to average {{convert|444|g|oz|abbr=on}}, were secondary in number to unidentified small rodents but red-tails in the region killed an estimated 22–60% of the area's ground squirrel, a large dent in the squirrel's population.<ref name="Luttich"> {{cite journal|author=Luttich, S., Rusch, D. H., Meslow, E. C., & Keith, L. B. |title=Ecology of Red-Tailed Hawk Predation in Alberta|journal=Ecology|volume=51|issue=2|pages=190–203|doi=10.2307/1933655|jstor=1933655|year=1970|bibcode=1970Ecol...51..190L }}</ref> Further east, ground squirrels are not so reliably distributed, but one study in southern [[Wisconsin]], in one of several quite different dietary studies in that state, the {{convert|172.7|g|oz|abbr=on}} [[thirteen-lined ground squirrel]] (''Ictidomys tridecemlineatus'') was the main prey species, making up 29.7% of the diet (from a sample of 165).<ref name="Errington"> {{cite journal|author=Errington, P. L., & Breckenridge, W. J. |year=1938|title=Food habits of Buteo hawks in north-central United States|jstor=4156719|url=https://sora.unm.edu/node/126125|journal=The Wilson Bulletin|volume= 50|issue=2|pages=113–121}}</ref><ref name="Wooton"> {{cite journal|author=Wootton, J. T.|title=The Effects of Body Mass, Phylogeny, Habitat, and Trophic Level on Mammalian Age at First Reproduction|journal=Evolution; International Journal of Organic Evolution|volume=41|issue=4|pages=732–749|pmid=28564349|year=1987|doi=10.1111/j.1558-5646.1987.tb05849.x|s2cid=8217344|doi-access=free}}</ref> [[File:A Tasty Meal (9443720303).jpg|thumb|right|A red-tailed Hawk eating a [[Uinta ground squirrel]].]] In [[Kluane Lake]], [[Yukon]], {{convert|750|g|lb|abbr=on}} [[Arctic ground squirrel]]s (''Spermophilus parryii'') were the main overall food for Harlan's red-tailed hawks, making up 30.8% of a sample of 1074 prey items. When these ground squirrels enter their long hibernation, the breeding Harlan's hawks migrate south for the winter.<ref name= Doyle>Doyle, F. I. (2001). [https://open.library.ubc.ca/cIRcle/collections/ubctheses/831/items/1.0099513 ''Timing of reproduction by red-tailed hawks, northern goshawks and great horned owls in the Kluane Boreal Forest of Southwestern Yukon'']. PhD Thesis. University of British Columbia.</ref> Nearly as important in Kluane Lake was the {{convert|200|g|oz|abbr=on}} [[American red squirrel]] (''Tamiasciurus hudsonicus''), which constituted 29.8% of the above sample. Red squirrels are highly agile dwellers on dense spruce stands, which has caused biologists to ponder how the red-tailed hawks are able to routinely catch them. It is possible that the hawks catch them on the ground such as when squirrels are digging their caches, but theoretically, the dark color of the Harlan's hawks may allow them to ambush the squirrels within the forests locally more effectively.<ref name= Palmer/><ref name= Wooton/><ref name= Doyle/> While American red squirrels turn up not infrequently as supplementary prey elsewhere in North America, other [[tree squirrel]]s seem to be comparatively infrequently caught, at least during the summer breeding season. It is known that pairs of red-tailed hawks will cooperatively hunt tree squirrels at times, probably mostly between late fall and early spring. [[Fox squirrel]]s (''Sciurus niger''), the largest of North America's tree squirrels at {{convert|800|g|lb|abbr=on}}, are relatively common supplemental prey but the lighter, presumably more agile {{convert|533|g|lb|abbr=on}} [[eastern gray squirrel]] (''Sciurus carolinensis'') appears to be seldom caught based on dietary studies.<ref name="Preston" /><ref name="Orians" /><ref name="Errington" /><ref name="Wooton" /><ref name="Springer">{{cite journal |first1=Mark Andrew|last1= Springer |first2= John Stephen |last2=Kirkley |year=1978 |title=Inter and Intraspecific interactions between Red-Tailed Hawks and Great Horned Owls in Central Ohio |journal=The Ohio Journal of Science |volume=78 |issue=6 |pages=323–328 |hdl= 1811/22576 }}</ref> While adult marmot may be difficult for red-tailed hawks to catch, young marmots are readily taken in numbers after weaning, such as a high frequency of [[yellow-bellied marmot]] (''Marmota flaviventris'') in [[Boulder, Colorado]].<ref name="Boulder">{{cite journal|author=Blumstein, D. T.|url=https://sora.unm.edu/node/53130 |year=1989|title=Food habits of red-tailed hawks in Boulder County, Colorado|journal=J. Raptor Res.|volume= 23|pages= 53–55}}</ref> Another grouping of [[squirrel]]s but at the opposite end of the size spectrum for squirrels, the [[chipmunk]]s are also mostly supplemental prey but are considered more easily caught than tree squirrels, considering that they are more habitual terrestrial foragers.<ref name="Palmer" /><ref name="CRPreston" /><ref name="Sherrod" /> In central [[Ohio]], [[eastern chipmunk]]s (''Tamias striatus''), the largest species of chipmunk at an average weight of {{convert|96|g|oz|abbr=on}}, were actually the leading prey by number, making up 12.3% of a sample of 179 items.<ref name="Springer" /><ref>{{cite journal|author=White, C. R., & Seymour, R. S.|title=Mammalian basal metabolic rate is proportional to body mass2/3|journal=Proceedings of the National Academy of Sciences of the United States of America|volume=100|issue=7|pages=4046–9|pmid=12637681|pmc=153045|year=2003|doi=10.1073/pnas.0436428100|bibcode=2003PNAS..100.4046W|doi-access=free}}</ref> Outside of rodents, the most important prey for North American red-tailed hawks is [[rabbits and hares]], of which at least 13 species are included in their prey spectrum. By biomass and reproductive success within populations, these are certain to be their most significant food source (at least in North America).<ref name="Preston" /><ref name="Sherrod" /> Adult ''[[Sylvilagus]]'' rabbits known to be hunted by red-tails can range from the {{convert|700|g|lb|abbr=on}} [[brush rabbit]] (''Sylvilagus bachmani'') to the [[Tres Marias rabbit]] (''Sylvilagus graysoni'') at {{convert|1470|g|lb|abbr=on}} while all leporids hunted may range the {{convert|421.3|g|oz|abbr=on}} [[pygmy rabbit]] (''Brachylagus idahoensis'') to hares and jackrabbits potentially up twice the hawk's own weight.<ref>{{cite journal|author=Chapman, J. A. |year=1974|title=''Sylvilagus bachmani''|journal= Mammalian Species|issue=34|pages= 1–4|doi=10.2307/3503777|jstor=3503777|s2cid=253951145 |doi-access=free}}</ref><ref>{{cite journal|author=Cervantes, F. A. |year=1997|title= ''Sylvilagus graysoni''|journal= Mammalian Species|issue=559|pages= 1–3|doi=10.2307/3504378|jstor=3504378|doi-access=free}}</ref><ref>{{cite journal|author=Green, J. S., & Flinders, J. T. |year=1980|title=''Brachylagus idahoensis''|journal= Mammalian Species|issue=125|pages=1–4|doi=10.2307/3503856|jstor=3503856|doi-access=free}}</ref><ref name="Steenhof" /> While primarily [[crepuscular]] in peak activity, rabbits and hares often foraging both during day and night and so face almost constant predatory pressure from a diverse range of predators. Male red-tailed hawks or pairs which are talented rabbit hunters are likely to have higher than average productivity due to the size and nutrition of the meal ensuring healthy, fast-growing offspring.<ref name="Palmer" /><ref name="Preston" /><ref name="Craighead" /><ref>{{cite journal|author=Bond, B. T., Burger Jr, L. W., Leopold, B. D., & Godwin, K. D. |title=Survival of cottontail rabbits (''Sylvilagus floridanus'') in Mississippi and an examination of latitudinal variation|journal=The American Midland Naturalist|volume=145|issue=1|pages=127–136|doi=10.1674/0003-0031(2001)145[0127:SOCRSF]2.0.CO;2|jstor=3083087|year=2001|s2cid=85350543 }}</ref> Most widely reported are the [[cottontail]]s, which the three most common North America varieties softly grading into mostly allopatric ranges, being largely segregated by habitat preferences where they overlap in distribution. Namely, in descending order of reportage were: the [[eastern cottontail]] (''Sylvilagus floridanus''), the second most widely reported prey species overall in North America and with maximum percentage known in a given study was 26.4% in [[Oklahoma]] (out of 958 prey items), the [[mountain cottontail]] (''Sylvilagus nuttallii''), maximum representation being 17.6% out of a sample of 478 in [[Kaibab Plateau]], [[Arizona]] and the [[desert cottontail]] (''Sylvilagus audubonii''), maximum representation being 22.4% out of a sample of 326 in west-central [[Arizona]].<ref name="Sherrod" /><ref name="Seidensticker" /><ref name="Gatto">{{cite journal |first1=Angela E. |last1=Gatto|first2=Teryl G. |last2=Grubb |first3=Carol L.|last3= Chambers |year=2006 |title=Red-tailed Hawk dietary overlap with Northern Goshawks on the Kaibab Plateau, Arizona |journal=Journal of Raptor Research |volume=39 |issue=4 |pages=439–444 |url=https://sora.unm.edu/node/54211}}</ref><ref>Millsap, B. A. (1981). [https://archive.org/details/distributionalst00mill ''Distributional status of falconiformes in westcentral Arizona: with notes on ecology, reproductive success and management'']. US Bureau of Land Management, Phoenix District Office.</ref> [[Black-tailed jackrabbit]]s (''Lepus californicus'') are even more intensely focused upon as a food source by the hawks found in the west, particularly the [[Great Basin]].<ref name="Smith" /> With the weight around {{convert|2114|g|lb|abbr=on}}, adults of this species is the largest prey routinely hunted by red-tailed hawks.<ref name="Fitzner" /><ref name="Steenhof2" /> When jackrabbit numbers crash, red-tailed hawk productivity tends to decline as well.<ref>Smith, Dwight G., and Joseph R. Murphy. "BREEDING RESPONSES OF RAPTORS TO JACKRABBIT DENSITY." Raptor Research 13.1 (1979): 1–14.</ref> In northern [[Utah]], black-tailed jackrabbits made up 55.3% of a sample of 329. Elsewhere, they are usually somewhat secondary by number.<ref name="Sherrod" /> [[File:Red-tailed Hawk (juvenile) on Seedskadee National Wildlife Refuge (28922103625).jpg|thumb|left|A juvenile after it ate its [[mountain cottontail]] prey.]] In the [[boreal forests]] of Canada and [[Alaska]], red-tails are fairly dependent on the [[snowshoe hare]] (''Lepus americanus''), falling somewhere behind the [[great horned owl]] and ahead of the [[American goshawk]] in their regional reliance on this food source.<ref name= Lowe/><ref name= Doyle/><ref name= Luttich/> The hunting preferences of red-tails who rely on snowshoe hares are variable. In [[Rochester, Alberta]], 52% of snowshoe hares caught were adults, such prey estimated to average {{convert|1287|g|lb|abbr=on}}, and adults, in some years, were six times more often taken than juvenile hares, which averaged an estimated {{convert|560|g|lb|abbr=on}}. 1.9–7.1% of adults in the regional population of Rochester were taken by red-tails, while only 0.3–0.8 of juvenile hares were taken by them. Despite their reliance on it, only 4% (against 53.4% of the biomass) of the food by frequency here was made up of hares.<ref name= Luttich/> On the other hand, in Kluane Lake, [[Yukon]], juvenile hares were taken roughly 11 times more often than adults, despite the larger size of adults here, averaging {{convert|1406.6|g|lb|abbr=on}}, and that the overall prey base was less diverse at this more northerly clime. In both Rochester and Kluane Lake, the number of snowshoe hares taken was considerably lower than the number of ground squirrels taken. The differences in average characteristics of snowshoe hares that were hunted may be partially due to habitat (extent of [[bog]] openings to dense forest) or topography.<ref name= Doyle/><ref>{{cite journal|author=Krebs, C. J., Boutin, S., & Boonstra, R.|title=Population Cycles in Ecosystem Context|journal=Ecology|volume=83|issue=7|pages=2064–2065|doi=10.2307/3071790|jstor=3071790|year=2002}}</ref> Another member of the [[Lagomorpha]] order has been found in the diet include juvenile [[white-tailed jackrabbit]] (''Lepus townsendii'') and the much smaller [[American pika]] (''Ochotona princeps''), at {{convert|150|g|oz|abbr=on}}.<ref name= Restani/><ref>Murphy, Robert K. "Prey of nesting red-tailed hawks and great horned owls on Lostwood National Wildlife Refuge, north-western North Dakota." Blue jay 55.3 (1997).</ref><ref>{{cite journal|author=Smith, A. T., & Weston, M. L. |year=1990|title=''Ochotona princeps''|journal= Mammalian Species|issue=352|pages=1–8|doi=10.2307/3504319|jstor=3504319|doi-access=free}}</ref> [[File:Payback - Flickr - Bien Stephenson.jpg|thumb|right|A red-tailed hawk feeding on its prey, a young [[cat]].]] A diversity of mammals may be consumed opportunistically outside of the main food groups of rodents and leporids, but usually occur in low numbers. At least five species each are taken of [[shrew]]s and [[mole (animal)|mole]]s, ranging in size from their smallest mammalian prey, the [[Cinereus shrew|cinereus]] (''Sorex cinereus'') and [[least shrew]]s (''Cryptotis parva''), which both weigh about {{convert|4.4|g|oz|abbr=on}}, to [[Townsend's mole]] (''Scapanus townsendii''), which weighs about {{convert|126|g|oz|abbr=on}}.<ref name= Sherrod/><ref name= Blumstein/><ref>Committee on the Status of Endangered Wildlife in Canada (COSEWIC). [http://www.registrelep-sararegistry.gc.ca/document/default_e.cfm?documentID=184 ''COSEWIC Assessment and Update Status Report on the Townsend's Mole in Canada'']. 0-662-33588-0. Ottawa: Environment Canada. 2003.</ref><ref>{{cite journal|author=Carraway, L. N., Alexander, L. F., & Verts, B. J. |year=1993|title=''Scapanus townsendii''|journal= Mammalian Species|issue=434|pages= 1–7|doi=10.2307/3504286|jstor=3504286}}</ref><ref>{{cite journal|author=McCay, T. S. |year=2001|title= ''Blarina carolinensis''|journal= Mammalian Species|volume=673|pages= 1–7|doi=10.1644/1545-1410(2001)673<0001:BC>2.0.CO;2|s2cid=198969062 }}</ref><ref name= NVirginia>{{cite web |url=http://www2.fcps.edu/islandcreekes/ecology/organism_menu.htm |title=Study of North Virginia Ecology |publisher=Fairfax County Public Schools |access-date=2018-01-08 |archive-date=22 May 2017 |archive-url=https://web.archive.org/web/20170522231033/http://www2.fcps.edu/islandcreekes/ecology/organism_menu.htm |url-status=dead }}</ref> A respectable number of the {{convert|90|g|oz|abbr=on}} [[eastern mole]] (''Scalopus aquaticus'') were recorded in studies from [[Oklahoma]] and [[Kansas]].<ref name= Sherrod/><ref name= Bare/> Four species of bat have been recorded in their foods.<ref name= Sherrod/><ref name= Fitch/> The red-tailed hawks local to the large cave colonies of {{convert|12.3|g|oz|abbr=on}} [[Mexican free-tailed bat]]s (''Tadarida brasiliensis'') in Texas can show surprising agility, some of the same hawks spending their early evening and early morning hours in flight patrolling the cave entrances to stoop suddenly on these flighted mammals.<ref name= Lee/><ref name= Twente/><ref>{{cite journal|author=Wilkins, K. T. |year=1989|title= ''Tadarida brasiliensis''|journal= Mammalian Species|issue=331|pages= 1–10|doi=10.2307/3504148|jstor=3504148}}</ref> Larger miscellaneous mammalian prey are either usually taken as juveniles, like the [[nine-banded armadillo]] (''Dasypus novemcinctus''), or largely as [[carrion]], like the [[Virginia opossum]] (''Didelphis virginiana'').<ref name="NVirginia" /><ref>McDonough, C. M., & Loughry, W. J. (2013). ''The nine-banded armadillo: a natural history (Vol. 11)''. University of Oklahoma Press.</ref> Small [[carnivora]]ns may be taken, usually consisting of much smaller [[mustelid]]s, like the [[least weasel]]s (''Mustela nivalis''), [[stoat]]s (''Mustela erminea''), and [[long-tailed weasel]]s (''Neogale frenata'').<ref name="Sherrod" /><ref name="Steenhof2" /><ref name="Gatto" /><ref>Powell, Roger A. "Evolution of black-tipped tails in weasels: predator confusion." The American Naturalist 119.1 (1982): 126–131.</ref> Slightly larger carnivores, such as [[small Indian mongoose]]s (''Herpestes auropunctatus''), [[ringtail]]s (''Bassariscus astutus''), [[American mink]]s (''Neovison vison'') are known to be taken.<ref>Santana, Eduardo, and Stanley A. Temple. "Breeding biology and diet of Red-tailed Hawks in Puerto Rico." Biotropica (1988): 151–160.</ref><ref name="Gatto" /><ref>Errington, Paul L., and Walter John Breckenridge. "Food habits of Buteo hawks in north-central United States." The Wilson Bulletin 50.2 (1938): 113–121.</ref><ref>{{cite web|title=Red-tailed Hawk vs. Mink|url=https://www.ficonservancy.org/2018/08/red-tailed-hawk-v-mink/|publisher=fishers island conservancy|date=August 2018}}</ref> Even adult [[striped skunk]] (''Mephitis mephitis''), which can be much larger than a fully grown hawk, was reportedly killed and consumed by red-tailed hawks.<ref>Platt, Steven G., and Thomas R. Rainwater. "RED-TAILED HAWK PREDATION OF A STRIPED SKUNK." (2012).</ref> Additionally, red-tailed hawks are considered as potential predators of [[white-nosed coati]] (''Nasua narica'') and [[kit fox]] (''Vulpes macrotis'')<ref>{{cite journal|author=Hass, C. C., & Valenzuela, D. |title=Anti-predator benefits of group living in white-nosed coatis (''Nasua narica'')|journal=Behavioral Ecology and Sociobiology|volume=51|issue=6|pages=570–578|doi=10.1007/s00265-002-0463-5|year=2002|bibcode=2002BEcoS..51..570H |s2cid=13646837}}</ref><ref>{{cite journal|author=Hall, L. K., Day, C. C., Westover, M. D., Edgel, R. J., Larsen, R. T., Knight, R. N., & McMillan, B. R. |title=Vigilance of kit foxes at water sources: A test of competing hypotheses for a solitary carnivore subject to predation|journal=Behavioural Processes|volume=94|pages=76–82|pmid=23305800|year=2013|doi=10.1016/j.beproc.2012.12.007|s2cid=42678659}}</ref> Remains of exceptionally large carnivoran species, such as [[domestic cat]]s (''Felis catus''), [[red fox]] ('' Vulpes vulpes'') and [[common raccoon]] (''Procyon lotor'') are sometimes found amongst their foods, but most are likely taken as juveniles or consumed only as carrion.<ref name="Blumstein" /><ref name="Boulder" /><ref name="Bildstein">Bildstein, K. L. (1987). Behavioral ecology of red-tailed hawks (''Buteo jamaicensis''), rough-legged hawks (''Buteo lagopus''), northern harriers (''Circus cyaneus''), and American kestrels (''Falco sparverius'') in south central Ohio (No. 04; USDA, QL696. F3 B5.).</ref> Many of these medium-sized carnivorans are probably visited as roadkill, especially during the sparser winter months, but carrion has turned up more widely than previously thought. Some nests have been found (to the occasional "shock" of researchers) with body parts from large domestic stock like [[sheep]] (''Ovis aries''), [[pig]]s (''Sus domesticus''), [[horse]]s (''Equus caballus '') and [[cattle]] (''Bos taurus'') (not to mention wild varieties like [[deer]]), which red-tails must visit when freshly dead out on pastures and take a couple of talonfuls of meat.<ref name="Palmer" /><ref name="Gatto" /><ref name="Fitch" /><ref name="Bildstein" /> In one instance, a red-tailed hawk was observed to kill a small but seemingly healthy [[Sheep|lamb]]. These are born heavier than most red-tails at {{convert|1500|g|lb|abbr=on}} but in this case, the hawk was scared away before it could consume its kill by the rifle fire of the shepherd who witnessed the instance.<ref>{{cite journal|author=Barney, M.D. |year=1959|title=Red-tailed hawk killing a lamb|url=https://sora.unm.edu/node/101093|journal= Condor|volume= 61|pages= 157–158}}</ref> ===Birds=== [[File:A hawk eats a pigeon, near Toronto harbour.jpg|thumb|A hawk eats a [[feral pigeon]], near Toronto harbour]] Like most ''[[Buteo]]'' hawks, red-tailed hawks do not primarily hunt birds in most areas, but can take them fairly often whenever they opportune upon some that are vulnerable. Birds are, by far, the most diverse class in the red-tailed hawk's prey spectrum, with well over 200 species known in their foods.<ref name= Bent/><ref name= Sherrod/><ref name= Blumstein/> In most circumstances where birds become the main food of red-tailed hawks, it is in response to ample local populations of [[galliforms]]. As these are meaty, mostly terrestrial birds which usually run rather than fly from danger (although all wild species in North America are capable of flight), galliforms are ideal avian prey for red-tails. Some 23 species of galliforms are known to be taken by red-tailed hawks, about a third of these being species introduced by humans.<ref name= Sherrod/><ref name= Blumstein/> [[New World quail|Native quails]] of all five North American species may expect occasional losses.<ref name= Fitch/><ref>{{cite journal|author=Holdermann, D.A. & Holdermann, C.E. |year=1993|title=Immature Red-tailed Hawk captures Montezuma Quail|journal=NMOS Bulletin |volume=21|pages= 31–33}}</ref><ref>Rollins, D., Taylor, B. D., Sparks, T. D., Buntyn, R. J., Lerich, S. E., Harveson, L. A., Waddell, T.E. & Scott, C. B. (2009). [https://trace.tennessee.edu/cgi/viewcontent.cgi?referer=https://www.google.com/&httpsredir=1&article=1347&context=nqsp "Survival of female scaled quail during the breeding season at three sites in the Chihuahuan Desert"]. In National Quail Symposium Proceedings. Vol. 6, No. 1, p. 48.</ref> All 12 species of [[grouse]] native to North America are also occasionally included in their prey spectrum.<ref name= Doyle/><ref name= Restani/><ref name= McCluskey>{{cite journal|author=McCluskey C.|url=https://sora.unm.edu/node/52717|year=1979|title=Red-tailed Hawk preys on adult Sage Grouse in northern Utah|journal=Raptor Research |volume=13|pages= 123}}</ref><ref>{{cite journal|author=Conover, M. R., & Borgo, J. S. |title=Do Sharp-Tailed Grouse Select Loafing Sites to Avoid Visual or Olfactory Predators|journal=Journal of Wildlife Management|volume=73|issue=2|pages=242–247|doi=10.2193/2008-049|year=2009|bibcode=2009JWMan..73..242C |s2cid=44811741}}</ref><ref>{{cite journal|author=Wolfe, D. H., Patten, M. A., Shochat, E., Pruett, C. L., & Sherrod, S. K. |title=Causes and patterns of mortality in lesser prairie-chickens ''Tympanuchus pallidicinctus'' and implications for management|journal=Wildlife Biology|volume=13|pages=95–104|doi=10.2981/0909-6396(2007)13[95:CAPOMI]2.0.CO;2|year=2007|s2cid=35346957 |doi-access=free}}</ref><ref>Zwickel, Fred C. and James F. Bendell. (2018). "Sooty Grouse (''Dendragapus fuliginosus'')". In ''The Birds of North America''. {{doi|10.2173/bna.soogro1.02.1}}</ref><ref>Martin, K., Leslie A. Robb, Scott Wilson and Clait E. Braun. (2015). "White-tailed Ptarmigan (''Lagopus leucura'')". In ''The Birds of North America''. {{doi|10.2173/bna.68}}</ref><ref>Johnson, Jeff A., Michael A. Schroeder and Leslie A. Robb. (2011). "Greater Prairie-Chicken (''Tympanuchus cupido'')". In ''The Birds of North America''. {{doi|10.2173/bna.36}}</ref><ref>{{cite web |url=http://sagegrouseinitiative.com/content/behavior |title=Sage Grouse Behavior |publisher=The Sage Grouse Initiative |access-date=2018-01-08 |archive-date=19 August 2013 |archive-url=https://web.archive.org/web/20130819183643/http://sagegrouseinitiative.com/content/behavior |url-status=dead }}</ref> [[File:Red-tailed Hawk, Mountain View, California, United States imported from iNaturalist photo 14959341.jpg|thumb|Eating an [[American coot]]]] In the state of [[Wisconsin]], two large studies, from [[Waupun]] and [[Green County, Wisconsin|Green County]], found the main prey species to be the [[ring-necked pheasant]] (''Phasianus colchicus''), making up 22.7% of a sample of 176 and 33.8% of a sample of 139, respectively.<ref name="Orians" /><ref name="Gates">{{cite journal|author=Gates, J. M. |year=1972|jstor=4160255|title=Red-tailed hawk populations and ecology in east-central Wisconsin|url=https://sora.unm.edu/node/128893|journal= The Wilson Bulletin|volume=84|issue=4|pages= 421–433}}</ref> With a body mass averaging {{convert|1135|g|lb|abbr=on}}, adult pheasants are among the largest meals that male red-tails are likely to deliver short of adult rabbits and hares and therefore these nests tend to be relatively productive. Despite being not native to North America, pheasants usually live in a wild state. Chickens (''Gallus gallus domesticus'') are also taken throughout North America,<ref name="Extension-predators">{{cite web | title=Predator Management for Small and Backyard Poultry Flocks | website=[[Cooperative Extension]] Poultry | url=http://poultry.extension.org/articles/poultry-management/predator-management-for-small-and-backyard-poultry-flocks/ | access-date=2022-04-21}}</ref> with all Wisconsin studies also found large numbers of them, making up as much as 14.4% of the diet. Many studies reflect that free-ranging chickens are vulnerable to red-tailed hawks although somewhat lesser numbers are taken by them overall in comparison to nocturnal predators (i.e. [[Great horned owl|owl]]s and [[Red fox|foxes]]) and [[American goshawk|goshawk]]s.<ref name="Orians" /><ref name="Marti95" /><ref name="Gates" /> In [[Rochester, Alberta]], fairly large numbers of [[ruffed grouse]] (''Bonasa umbellus'') were taken but relatively more juveniles were taken of this species than the two other main contributors to biomass here, snowshoe hare and Townsend's ground squirrel, as they are fairly independent early on and more readily available. Here the adult grouse was estimated to average {{convert|550|g|lb|abbr=on}} against the average juvenile which in mid-summer averaged {{convert|170|g|oz|abbr=on}}.<ref name="Luttich" /> Beyond galliforms, three other quite different families of birds make the most significant contributions to the red-tailed hawk's avian diet. None of these three families are known as particularly skilled or swift fliers, but are generally small enough that they would generally easily be more nimble in flight. One of these are the [[woodpecker]]s, if only for one species, the {{convert|131.6|g|oz|abbr=on}} [[northern flicker]] (''Colaptes auratus''), which was the best represented bird species in the diet in 27 North American studies and was even the fourth most often detected prey species of all.<ref name="Palmer" /><ref name="CRPreston" /><ref name="Sherrod" /><ref name="Blumstein" /> Woodpeckers are often a favorite in the diet of large raptors as their relatively slow, undulating flight makes these relatively easy targets. The flicker in particular is a highly numerous species that has similar habitat preferences to red-tailed hawks, preferring fragmented landscapes with trees and openings or parkland-type wooded mosaics, and often forage on the ground for ants, which may make them even more susceptible.<ref>{{cite journal|author=Fisher, R. J., & Wiebe, K. L. |title=Breeding dispersal of Northern Flickers ''Colaptes auratus'' in relation to natural nest predation and experimentally increased perception of predation risk|journal=Ibis|volume=148|issue=4|pages=772–781|doi=10.1111/j.1474-919X.2006.00582.x|year=2006}}</ref><ref>{{cite journal|author=Fisher, R. J., & Wiebe, K. L. |title=Nest site attributes and temporal patterns of northern flicker nest loss: Effects of predation and competition|url=https://archive.org/details/sim_oecologia_2006-04_147_4/page/744 |journal=Oecologia|volume=147|issue=4|pages=744–53|pmid=16323016|year=2006|doi=10.1007/s00442-005-0310-2|bibcode=2006Oecol.147..744F|s2cid=34064989}}</ref> Varied other woodpecker species may turn up in their foods, from the [[Downy woodpecker|smallest]] to the [[Pileated woodpecker|largest extant]] in North America, but are much more infrequently detected in dietary studies.<ref name="NVirginia" /><ref>{{cite journal|author=Brooks, A. |year=1944|title=A deplumed Pileated Woodpecker|url=https://sora.unm.edu/node/99511|journal= Condor|volume= 46|issue=3|pages= 124–130|doi=10.2307/1364279|jstor=1364279|url-access=subscription}}</ref> Another family relatively often selected prey family are [[corvid]]s, which despite their relatively large size, formidable mobbing abilities and intelligence are also slower than average fliers for passerines. 14 species of corvid are known to fall prey to red-tailed hawks.<ref name="Sherrod" /><ref name="Blumstein" /><ref>{{cite journal|author=Knight, R. L., & Kawashima, J. Y. |title=Responses of Raven and Red-Tailed Hawk Populations to Linear Right-of-Ways|url=https://archive.org/details/sim_journal-of-wildlife-management_1993-04_57_2/page/266 |journal=The Journal of Wildlife Management|volume=57|issue=2|pages=266–271|jstor=3809423|doi=10.2307/3809423|year=1993}}</ref> In the [[Kaibab Plateau]], the {{convert|128|g|oz|abbr=on}} [[Steller's jay]] (''Cyanocitta stelleri'') were the fourth most identified prey species (10.3% of the diet).<ref name="Gatto" /> {{convert|453|g|lb|abbr=on}} [[American crow]]s are also regularly detected supplemental prey in several areas.<ref name="Orians" /><ref name="Seidensticker" /><ref name="Gates" /> Even the huge [[common raven]] (''Corvus corax''), at {{convert|1050|g|lb|abbr=on}} at least as large as red-tailed hawk itself, may fall prey to red-tails, albeit very infrequently and only in a well-staged ambush.<ref name="Gatto" /> One of the most surprising heavy contributors are the [[icterid]]s, despite their slightly smaller size and tendency to travel in large, wary flocks, 12 species are known to be hunted.<ref name="Sherrod" /><ref name="Blumstein" /> One species pair, the [[meadowlark]]s, are most often selected as they do not flock in the same ways as many other icterids and often come to the ground, throughout their life history, rarely leaving about shrub-height. The {{convert|100.7|g|oz|abbr=on}} [[western meadowlark]] (''Sturnella neglecta''), in particular, was the third most often detected bird prey species in North America.<ref name="Palmer" /><ref name="CRPreston" /><ref name="Sherrod" /><ref name="Blumstein" /><ref name="Steenhof2" /> [[Red-winged blackbird]]s (''Agelaius phoeniceus'') which are probably too small, at an average weight of {{convert|52.4|g|oz|abbr=on}}, and fast for a red-tailed hawk to ever chase on the wing (and do travel in huge flocks, especially in winter) are nonetheless also quite often found in their diet, representing up to 8% of the local diet for red-tails. It is possible that males, which are generally bold and often select lofty perches from which to display, are most regularly ambushed.<ref name="Palmer" /><ref name="Gates" /> One bird species that often flocks with red-winged blackbirds in winter is even better represented in the red-tail's diet, the non-native {{convert|78|g|oz|abbr=on}} [[European starling]] (''Sturnus vulgaris''), being the second most numerous avian prey species and seventh overall in North America.<ref name="Sherrod" /><ref name="Blumstein" /> Although perhaps most vulnerable when caught unaware while calling atonally on a perch, a few starlings (or various blackbirds) may be caught by red-tails which test the agile, twisting [[Flocking (behavior)|murmurations]] of birds by flying conspicuously towards the flock, to intentionally disturb them and possibly detect lagging, injured individual birds that can be caught unlike healthy birds. However, this behavior has been implied rather than verified.<ref name="Palmer" /><ref name="Fitch" /> [[File:Red-tailed Hawk (Buteo jamaicensis) (8082138275).jpg|thumb|right|A red-tailed hawk with avian prey.]] Over 50 passerine species from various other families beyond corvids, icterids and starlings are included in the red-tailed hawks' prey spectrum but are caught so infrequently as to generally not warrant individual mention.<ref name= Sherrod/><ref name= Blumstein/> Non-passerine prey taken infrequently may include but are not limited to [[pigeon]]s and [[dove]]s, [[cuckoo]]s, [[nightjar]]s, [[Belted kingfisher|kingfishers]] and parrots.<ref name= Preston/><ref name= Steenhof2/><ref name= Fitch/><ref>Wiley, J. W., & Wiley, B. N. (1979). "The biology of the White-crowned Pigeon". ''Wildlife Monographs'', (64), 3–54.</ref><ref>{{cite journal|author=Snyder, L.L. |year=1926|url=https://sora.unm.edu/node/13636|title=Belted Kingfisher preyed upon by Red-tailed Hawk|journal=Auk|volume = 43|issue=1|pages= 97–98|doi=10.2307/4075306|jstor=4075306|url-access=subscription}}</ref><ref>{{cite journal|author=Rodriguez-Estrella, R., de la Luz, J. L. L., Breceda, A., Castellanos, A., Cancino, J., & Llinas, J. |title=Status, density and habitat relationships of the endemic terrestrial birds of Socorro Island, Revillagigedo Islands, Mexico|journal=Biological Conservation|volume=76|issue=2|pages=195–202|doi=10.1016/0006-3207(95)00104-2|year=1996|bibcode=1996BCons..76..195R }}</ref><ref>Snyder, Noel F., Ernesto C. Enkerlin-Hoeflich and M. A. Cruz-Nieto. (1999). "Thick-billed Parrot (''Rhynchopsitta pachyrhyncha'')". In ''The Birds of North America''. {{doi|10.2173/bna.406}}</ref> However, of some interest, is the extreme size range of birds that may be preyed upon. Red-tailed hawks in Caribbean islands seem to catch small birds more frequently due to the paucity of vertebrate prey diversity here. Birds as small as the {{convert|7.7|g|oz|abbr=on}} [[elfin woods warbler]] (''Setophaga angelae'') and the {{convert|10|g|oz|abbr=on}} [[bananaquit]] (''Coereba flaveola'') may turn up not infrequently as food. How red-tails can catch prey this small and nimble is unclear (perhaps mostly the even smaller nestlings or fledglings are depredated).<ref name= Palmer/><ref name= Preston/><ref name= Santana/> In California, most avian prey was stated to be between the size of a [[European starling|starling]] and a [[California quail|quail]].<ref name= Palmer/><ref name= Fitch/> Numerous [[water bird]]s may be preyed upon including at least 22 species of [[Charadriiformes|shorebirds]], at least 17 species of [[waterfowl]], at least 8 species of [[heron]] and [[egret]]s and at least 8 species of [[Rail (bird)|rails]], plus a smaller diversity of [[grebe]]s, [[Townsend's shearwater|shearwaters]] and [[White-faced ibis|ibises]].<ref name= Palmer/><ref name= Sherrod/><ref name= Blumstein/><ref>{{cite journal|author=Martınez-Gomez, J. E., & Jacobsen, J. K. |title=The conservation status of Townsend's shearwater ''Puffinus auricularis auricularis''|journal=Biological Conservation|volume=116|pages=35–47|doi=10.1016/S0006-3207(03)00171-X|year=2004|issue=1 |bibcode=2004BCons.116...35M }}</ref> These may range to as small as the tiny, mysterious and "mouse-like" [[black rail]] (''Laterallus jamaicensis''), weighing an average of {{convert|32.7|g|oz|abbr=on}}, and [[snowy plover]] (''Charadrius nivosus''), weighing an average of {{convert|42.3|g|oz|abbr=on}} (how they catch adults of this prey is not known), to some [[gull]]s, [[duck]]s and [[geese]] as heavy or heavier than a red-tailed hawk itself.<ref>Evens, J. G., & Thorne, K. M. (2015). "Case Study, California Black Rail (''Laterallus jamaicensis corturniculus'')". Science Foundation Chapter 5, Appendix 5.1 in ''The Baylands and climate change: What can we do?''. California State Coastal Conservancy.</ref><ref>Page, Gary W., Lynne E. Stenzel, J. S. Warriner, J. C. Warriner and P. W. Paton. (2009). "Snowy Plover (''Charadrius nivosus'')". In ''The Birds of North America''. {{doi|10.2173/bna.154}}</ref> How large of a duck that red-tailed hawks can capture may be variable. In one instance, a red-tailed hawk failed to kill a healthy drake [[red-breasted merganser]] (''Mergus serrator''), with this duck estimated to weigh {{convert|1100|g|lb|abbr=on}}, later the same red-tail was able to dispatch a malnourished [[red-necked grebe]] (''Podiceps grisegena'') (a species usually about as heavy as the merganser), weighing an estimated {{convert|657|g|lb|abbr=on}}.<ref>{{cite journal |last=Jehl |first=J.R., Jr. |year=2004 |title=Foraging by a Red-tailed hawk along a wetland edge: How large a duck can be captured? |journal=[[The Wilson Bulletin]] |volume=116 |issue=4 |pages=354–356 |doi=10.1676/04-040 |jstor=4164700 |s2cid=86248829}}</ref> However, in interior Alaska, locally red-tailed hawks have become habitual predators of adult ducks, ranging from {{convert|345|g|oz|abbr=on}} [[green-winged teal]] (''Anas carolinensis'') to {{convert|1141|g|lb|abbr=on}} [[mallard]] (''Anas platyrhynchos'').<ref name= Lowe/> Even larger, occasionally adult [[Ross's goose]] (''Chen rossii''), weighing on average {{convert|1636|g|lb|abbr=on}}, have been killed as well.<ref>{{cite journal |last1=Jónsson |first1=J.E. |last2=Afton |first2=A.D. |year=2008 |title=Lesser snow geese and Ross's geese form mixed flocks during winter but differ in family maintenance and social status |journal=[[The Wilson Journal of Ornithology]] |volume=120 |issue=4 |pages=725–731 |doi=10.1676/07-124.1 |s2cid=55754017}}</ref> Also, a non-native [[Egyptian goose]] (''Alopochen aegyptiaca''), in which adults average {{convert|1762|g|lb|abbr=on}}, was killed by a red-tail in [[Texas]].<ref>{{cite journal|author=Callaghan, C. T., & Brooks, D. M. |year=2016|title=Ecology, behavior, and reproduction of invasive Egyptian Geese (''Alopochen aegyptiaca'') in Texas|journal= Bulletin of the Texas Ornithological Society|volume= 49|pages=37–45}}</ref> There are several known instances of predation on young [[greater sage grouse]] (''Centrocercus urophasianus''), and predation on an adult female, weighing {{convert|1500|g|lb|abbr=on}} have been reported.<ref name= McCluskey/> Even larger, in at least one case a grown hatch-year bird was caught of the rare, non-native [[Himalayan snowcock]] (''Tetraogallus himalayensis''), this species averaging {{convert|2428|g|lb|abbr=on}} in adults.<ref>Christensen, Glen C. (1998). "Himalayan Snowcock (''Tetraogallus himalayensis'')". In ''The Birds of North America''. {{doi|10.2173/bna.328}}</ref> Red-tailed hawks are a threat to the poults typically of the [[wild turkey]] (''Meleagris gallopavo''), which weighed up to at least {{convert|1500|g|lb|abbr=on}}.<ref>{{cite journal|author=Hargrave, L.L. |year=1935|title=Red-tailed hawk kills young turkey|journal=Condor|volume= 37|issue=2|pages= 83|url=https://sora.unm.edu/node/98332|doi=10.2307/1363880|jstor=1363880|url-access=subscription}}</ref> In one instance, a red-tailed hawk was observed trying to attack an adult female turkey, but not succeed at dispatching her.<ref>{{cite journal|author=Cherry, M.J., Lane, V.R., Warren, R.J. & Conner, L.M. |year=2011|title=Red-tailed hawk attacks Wild Turkey on bait: Can Baiting Affect Predation Risk?|journal=The Oriole|volume= 77|pages= 19–24|url=https://sora.unm.edu/node/138801}}</ref> Other than turkeys, other larger birds occasionally lose young to red-tails such as [[trumpeter swan]]s (''Cygnus buccinator''), [[sandhill crane]]s (''Grus canadensis'') and [[great blue heron]]s (''Ardea herodias'').<ref>Mitchell, Carl D. and Michael W. Eichholz. (2010). "Trumpeter Swan (''Cygnus buccinator'')". In ''The Birds of North America''. {{doi|10.2173/bna.105}}</ref><ref>Gerber, Brian D., James F. Dwyer, Stephen A. Nesbitt, Rod C. Drewien, Carol D. Littlefield, T. C. Tacha and P. A. Vohs. (2014). "Sandhill Crane (''Antigone canadensis'')". In ''The Birds of North America''. {{doi|10.2173/bna.31}}</ref> ===Reptiles=== [[File:Red-tailed Hawk (7529235270).jpg|thumb|A red-tailed hawk feeding on its kill, a large colubrid snake]] [[File:Red-tailed Hawk imported from iNaturalist photo 3663761 on 2 December 2024.jpg|thumb|Hunting a [[bullsnake]]]] Early reports claimed relatively little predation of reptiles by red-tailed hawks but these were regionally biased towards the east coast and the upper Midwest of the United States.<ref name= Fisher>Fisher, A. K. (1893). ''Hawks and owls of the United States in their relation to agriculture''. U.S. Dept. of Agriculture Bull. 3. Government Printing Office, Washington, D.C.</ref> However, locally the predation on reptiles can be regionally quite heavy and they may become the primary prey where large, stable numbers of rodents and leporids are not to be found reliably. Nearly 80 species of reptilian prey have been recorded in the diet at this point.<ref name= Palmer/><ref name= Sherrod/><ref name= Blumstein/> Most predation is on snakes, with more than 40 species known in the prey spectrum. The most often found reptilian species in the diet (and sixth overall in 27 North American dietary studies) was the [[Pituophis catenifer|gopher snake]] (''Pituophis catenifer''). Red-tails are efficient predators of these large snakes, which average about {{convert|532|to|747|g|lb|abbr=on}} in adults, although they also take many small and young gopher snakes.<ref name= Steenhof2/><ref name= Fitzner/><ref name= Erickson>{{cite journal|author=Knight, R. L., & Erickson, A. W. |year=1976|title=High incidence of snakes in the diet of nesting red-tailed hawks|journal= Raptor Res|volume= 10|pages= 108–111|url=https://sora.unm.edu/node/52638}}</ref><ref>{{cite journal|author=Iverson, J. B., Young, C. A., & Akre, T. S. |year=2008|title=Body Size and Growth in the Bullsnake (''Pituophis catenifer sayi'') in the Nebraska Sandhills|jstor=40060543|journal= Journal of Herpetology|volume= 42|issue=3|pages= 501–507|doi=10.1670/07-030.1|s2cid=86184092}}</ref><ref name= Guthrie>{{cite journal |last=Guthrie |first=J.E. |year=1932 |title=Snakes versus birds; birds versus snakes |journal=[[The Wilson Bulletin]] |volume= 44 |issue=2 |pages= 88–113 |jstor=4156082 |url=https://sora.unm.edu/node/125607 |via=sora.unm.edu }}</ref><ref>{{cite journal |last1=Feldman |first1=A. |last2=Meiri |first2=S. |year=2013 |title=Length–mass allometry in snakes |journal=[[Biological Journal of the Linnean Society]] |volume=108 |issue=1 |pages=161–172 |doi=10.1111/j.1095-8312.2012.02001.x }}</ref> Along the [[Columbia River]] in [[Washington (state)|Washington]], large [[colubrid snakes]] were found to be the primary prey, with the [[eastern racer]] (''Coluber constrictor''), which averages about {{convert|556|g|lb|abbr=on}} in mature adults, the most often recorded at 21.3% of 150 prey items, followed by the gopher snake at 18%. This riverine region lacks ground squirrels and has low numbers of leporids. 43.2% of the overall diet here was made up of reptiles, while mammals, made up 40.6%.<ref name= Erickson/><ref>{{cite journal |last1=Carfagno |first1=G.L. |last2=Weatherhead |first2=P.J. |year=2008 |title=Energetics and space use: Intraspecific and interspecific comparisons of movements and home ranges of two Colubrid snakes |journal=[[The Journal of Animal Ecology]] |volume=77 |issue=2|pages=416–24 |pmid=18254921 |doi=10.1111/j.1365-2656.2008.01342.x |bibcode=2008JAnEc..77..416C }}</ref> In the [[Morley Nelson Snake River Birds of Prey National Conservation Area|Snake River NCA]], the gopher snake was the second most regularly recorded (16.2% of 382 items) prey species over the course of the years and did not appear to be subject to the extreme population fluctuations of mammalian prey here.<ref name= Steenhof2/> Good numbers of smaller colubrids can be taken as well, especially [[garter snake]]s.<ref name="Sherrod" /><ref name="Restani" /><ref name="Bare" /> Red-tailed hawks may engage in avoidance behavior to some extent with regard to [[venomous snake]]s. For example, on the [[San Joaquin Experimental Range]] in California, they were recorded taking 225 gopher snakes against 83 [[Crotalus oreganus|western rattlesnake]]s (''Crotalus oreganus''). Based on surveys, however, the rattlesnakes were five times more abundant on the range than the gopher snakes.<ref name="Palmer" /><ref name="Fitch" /> Nonetheless, the red-tailed hawk's diet has recorded at least 15 venomous snakes.<ref name="Sherrod" /><ref name="Blumstein" /> Several predation on adult [[rattlesnake]]s have reported, including adult [[eastern diamondback rattlesnake]] (''Crotalus adamanteus'') about {{convert|126.4|cm|ftin|0|abbr=on}} in snout-to-vent length.<ref>{{cite journal |last=Timmerman |first=W.W. |year=1995 |title=Home range, habitat use, and behavior of the eastern diamondback rattlesnake (''Crotalus adamanteus'') on the Ordway Preserve |journal=[[Bulletin of the Florida Museum of Natural History]] |volume=38 |issue=5 |pages=127–158 |doi=10.58782/flmnh.tvem1511 }}</ref> These rattlesnakes are the heaviest venomous snakes in America, with a mature size of about {{convert|2300|g|lb|abbr=on}}, and can be hazardous to hawks, though an immature red-tail was photographed killing a "fairly large" [[eastern diamondback rattlesnake]] in one instance.<ref name="delHoyo" /><ref>{{cite journal |last1=Heckel |first1=Jens-Ove |first2=D. Clay |last2=Sisson |first3=Charlotte F. |last3=Quist |year=1994 |title=Apparent fatal snakebite in three hawks |journal=[[Journal of Wildlife Diseases]] |volume=30 |issue=4 |pages=616–619 |doi=10.7589/0090-3558-30.4.616 |pmid=7760504 }}</ref><ref>{{cite journal |last1=Dorcas |first1=M.E. |last2=Hopkins |first2=W.A. |last3=Roe |first3=J.H. |year=2004 |title=Effects of body mass and temperature on standard metabolic rate in the eastern diamondback rattlesnake (''Crotalus adamanteus'') |journal=[[Copeia]] |volume=2004 |pages=145–151 |doi=10.1643/CP-03-074R1 |s2cid=51943383}}</ref> Additionally, [[eastern indigo snake]]s (''Drymarchon couperi''), North America's longest native snake can be taken as well.<ref>{{cite report |last1=Kendrick |first1=M.M. |last2=Mengak |first2=M.T. |year=2010 |title=Eastern indigo snake (''Drymarchon couperi'') |series=Warnell School of Forestry and Natural Resources |publisher=[[The University of Georgia]] |url=https://athenaeum.libs.uga.edu/handle/10724/30761 |via=athenaeum.libs.uga.edu }}</ref> While these large snakes are usually dispatched on the ground, red-tailed hawks have been seen flying off with snake prey that may exceed {{convert|153|cm|ftin|0|abbr=on}} in length in some cases.<ref name="Preston" /> At the opposite end of the scale in snake prey, the smallest known snake known to be hunted by red-tailed hawks is the {{convert|6|g|oz|abbr=on}} [[Storeria occipitomaculata|redbelly snake]] (''Storeria occipitomaculata'').<ref>{{cite book |last1=Linzey |first1=D.W. |last2=Clifford |first2=M.J. |year=1981 |title=Snakes of Virginia |publisher=University of Virginia Press |place=Charlottesville, VA }}</ref> In North America, fewer lizards are typically recorded in the foods of red-tailed hawks than are snakes, probably because snakes are considerably better adapted to cooler, seasonal weather, with an extensive diversity of lizards found only in the southernmost reaches of the [[contiguous United States]]. A fair number of lizards were recorded in the diet in southern California. Red-tails can be counted among the primary predatory threats to largish lizards in the United States such as the {{convert|245|g|oz|abbr=on}} [[Sauromalus ater|common chuckawalla]] (''Sauromalus ater'').<ref name= Blumstein/><ref name= Fitch/><ref>Hollingsworth, B. D. (1998). "The systematics of chuckwallas (''Sauromalus'') with a phylogenetic analysis of other iguanid lizards". ''Herpetological Monographs'', pp. 38–191.</ref><ref>{{cite journal|author=Cooper Jr, W., Van Wyk, J. H., Mouton, P. L. F., Al-Johany, A. M., Lemos-Espinal, J. A., Paulissen, M. A., & Flowers, M. |year=2000|title=Lizard antipredatory behaviors preventing extraction from crevices|url=https://archive.org/details/sim_herpetologica_2000-09_56_3/page/394 |journal=Herpetologica|volume=56|issue=3|pages= 394–401|jstor=3893416}}</ref> However, the red-tailed hawks ranging into the neotropics regularly take numerous species of lizards. This is especially true of hawks living on islands where small mammals do not naturally colonize. Insular red-tails commonly pluck up mostly tiny [[anole]]s, that may average only {{convert|1.75|to|43.5|g|oz|abbr=on}} in adult mass, depending on species.<ref name= Preston/><ref name= Santana/><ref>{{cite journal|author=Butler, M. A., & Losos, J. B. |title=Multivariate Sexual Dimorphism, Sexual Selection, and Adaptation in Greater Antillean Anolis Lizards|journal=Ecological Monographs|volume=72|issue=4|pages=541–559|doi=10.1890/0012-9615(2002)072[0541:MSDSSA]2.0.CO;2|year=2002}}</ref> Not all tropical lizards taken by red-tailed hawks are so dainty red-tailed hawks can prey on capable of taking lizards as large as [[Ctenosaura hemilopha|Cape spinytail iguanas]] (''Ctenosaura hemilopha'') and [[green iguana]]s (''Iguana iguana'') that usually weighs between {{convert|700|to|1000|g|lb|abbr=on}} and around {{convert|1530|g|lb|abbr=on}} respectively.<ref>{{cite journal|author=Powell, R. & Henderson, R.W. |year=2008|title=Avian predators of West Indian reptiles|url=http://www.anoleannals.org/wp-content/uploads/2013/04/Powell-and-Henderson.-2008.pdf|journal=Iguana|volume= 15 |issue=1|pages= 9–12}}</ref><ref>Blázquez, M. Carmen, Ricardo Rodríguez‐Estrella, and Miguel Delibes. "Escape behavior and predation risk of mainland and island spiny‐tailed iguanas (Ctenosaura hemilopha)." Ethology 103.12 (1997): 990–998.</ref><ref>{{cite journal|url=https://www.tau.ac.il/lifesci/departments/zoology/members/meiri/documents/Meiri2010lizardweightSVLallometry_000.pdf|author=Meiri, S. |title=Length-weight allometries in lizards |journal=Journal of Zoology |doi=10.1111/j.1469-7998.2010.00696.x|year=2010 |volume=281 |issue=3 |pages=218–226 }}</ref> Beyond snakes and lizards, there are a few cases of red-tailed hawks preying on baby or juvenile turtles, i.e. the [[gopher tortoise]] (''Gopherus polyphemus''), the [[desert tortoise]] (''Gopherus agassizii'') and the [[common snapping turtle]] (''Chelydra serpentina'').<ref name= NVirginia/><ref>{{cite journal|author=Fitzpatrick, J. W., & Woolfenden, G. E. |year=1978|title=Red-tailed hawk preys on juvenile gopher tortoise|journal=Florida Field Naturalist|volume= 6|pages= 49|url=https://sora.unm.edu/node/133783}}</ref> ===Other prey=== [[File:Hawk fails to steal the fish (50380725913).jpg|thumb|right|A red-tailed hawk attempts unsuccessfully to pirate a fish from an [[osprey]].]] Records of predation on [[amphibian]]s is fairly infrequent. It is thought that such prey may be slightly underrepresented, as they are often consumed whole and may not leave a trace in pellets. Their fine bones may dissolve upon consumption.<ref name= Palmer/><ref name= Sherrod/><ref name= Fisher/> So far as is known, North American red-tailed hawks have preyed upon 9 species of amphibian, four of which are [[toad]]s. Known amphibian prey has ranged to as small as the {{convert|0.75|g|oz|abbr=on}} [[red-backed salamander]] (''Plethodon cinereus''), the smallest known vertebrate prey for red-tailed hawks, to the {{convert|430|g|oz|abbr=on}} [[American bullfrog]] (''Lithobates catesbeianus'').<ref name= Errington/><ref name= NVirginia/><ref>{{cite journal|author=Frost, D.R., Grant, T., Faivovich, J., Bain, R.H., Haas, A., Haddad, C.F.B., De Sá, R.O., Channing, A., Wilkinson, M., Donnellan, S.C., Raxworthy, C.J., Campbell, J.A., Blotto, B.L., Moler, P., Drewes, R.C., Nussbaum, R.A., Lynch, J.D., Green, D.M., Ward, C., Wheeler, W.C. |title=The Amphibian Tree of Life|journal=Bulletin of the American Museum of Natural History|volume=297|pages=1–291|doi=10.1206/0003-0090(2006)297[0001:TATOL]2.0.CO;2|hdl=2246/5781|year=2006|s2cid=86140137 |doi-access=free}}</ref> [[Invertebrate]]s, mostly represented by insects like [[beetle]]s and [[crickets]], are better represented in the stomach contents of red-tailed hawks than their pellets or prey remains.<ref name= Palmer/><ref name= Fisher/> It is possible some invertebrate prey is ingested incidentally, as in other various birds of prey, they can in some cases be actually from the stomachs of birds eaten by the raptor.<ref name= Ferguson-Lees/><ref name= Palmer/> However, some red-tails, especially immatures early in their hunting efforts, often do spend much of the day on the ground grabbing terrestrial insects and spiders.<ref name= Palmer/><ref name= Sherrod/><ref name= Fisher/><ref>{{cite journal|author=La Rivers, I. |year=1941|title=The Mormon cricket as food for birds|journal=The Condor|volume= 43|issue=1|pages=65–69|url=https://sora.unm.edu/node/99108|doi=10.2307/1364022|jstor=1364022}}</ref><ref>{{cite journal|author=Munro, J. A. |url=https://sora.unm.edu/node/97524|year=1929|title=Notes on the food habits of certain raptors in British Columbia and Alberta|journal=The Condor|volume= 31|issue=3|pages=112–116|doi=10.2307/1363092|jstor=1363092|url-access=subscription}}</ref>{{Excessive citations inline|date=April 2023}} The red-tailed hawks of [[Puerto Rico]] frequently consume [[Epilobocera sinuatifrons|Puerto Rican freshwater crabs]] (''Epilobocera sinuatifrons''), which average {{convert|9.4|g|oz|abbr=on}}.<ref name= Preston/><ref name= Santana/><ref>Fraiola, K. M. S. (2006). [https://getd.libs.uga.edu/pdfs/fraiola_kauaoa_m_200608_ms.pdf ''Juvenile Epilobocera sinuatifrons growth rates and ontogenetic shifts in feeding in wild populations'']. PhD Thesis, UGA.</ref> Other island populations, such as those on [[Socorro island]], also feed often on [[terrestrial crab]]s, here often blunting their claws while catching them.<ref name= Brown/> Fish are the rarest class of prey based on dietary studies. Among the rare instances of them capturing fish have included captures of wild [[channel catfish]] (''Ictalurus punctatus''), non-native [[common carp]] (''Cyprinus carpio'') and ornamental [[koi]] (''Cyprinus rubrofuscus'') as well some hawks that were seen scavenging on dead [[chum salmon]] (''Oncorhynchus keta'').<ref name= Blumstein/><ref>Tepper, J. M. (2015). "Predators of koi". In 40th World Small Animal Veterinary Association Congress, Bangkok, Thailand, 15–18 May 2015. Proceedings book. pp. 349–350. World Small Animal Veterinary Association.</ref><ref>{{cite journal|author=Stalmaster, M. V. |year=1980|title=Salmon carrion as a winter food source for red-tailed hawks|journal=The Murrelet|pages= 43–44}}</ref> ===Interspecies predatory relationships=== [[File:Red-shouldered Hawk harasses Red-tailed Hawk (50854764961).jpg|thumb|A [[red-shouldered hawk]] flies in to harass a red-tailed hawk, which often outcompetes and is occasionally dangerous to smaller raptors.]] As easily one of the most abundant of all American raptorial birds, red-tailed hawks have been recorded as interacting with every other diurnal bird of prey. Due to the extreme dietary plasticity of red-tails, the food habits of other birds of prey regularly overlap considerably with red-tails. Furthermore, due to its ability to nest in varied habitats, home ranges also frequently abut those of other raptor species.<ref name= Palmer/><ref name= Preston/> [[File:Red-tailed Hawk imported from iNaturalist photo 234593554 on 5 December 2024.jpg|thumb|Chasing a red-shouldered hawk]] The most obvious similar species in their range are other ''[[Buteo]]'' hawks, especially larger species with a similar ecological niche. Two of the larger, more widespread other ''Buteos'' are the [[Swainson's hawk]] and the [[ferruginous hawk]]s and, as with many other birds of prey, red-tailed hawks occur in almost the entirety of these birds' breeding ranges.<ref name="Preston" /><ref name="Johnsgard">{{cite book |first=P.A. |last=Johnsgard |author-link=Paul Johnsgard |year=1990 |title=Hawks, Eagles, & Falcons of North America: Biology and natural history |publisher=[[Smithsonian Institution]] }}</ref> These species have broadly similar breeding season diets, especially the ferruginous and red-tailed hawks. In some areas, such as [[Morley Nelson Snake River Birds of Prey National Conservation Area|Snake River NCA]] the diets of the two species consist of more than 90% of the same species and body mass of prey taken was similar.<ref name="Steenhof2" /><ref name="Restani" /> Therefore, all three large ''Buteo'' hawks defend their territories from each other with almost the same degree of dedication that they defend from others of their own species. In some cases, territorial clashes of Swainson's hawks and red-tailed hawks can last up to 12 hours, however, the birds involved are usually careful to avoid physical contact.<ref name="Palmer" /><ref name="Janes">{{cite journal |last=Janes |first=S.W. |year=1984 |title=Influences of territory composition and interspecific competition on Red-tailed hawk reproductive success |journal=Ecology |volume=65 |issue=3 |pages=862–870 |doi=10.2307/1938060 |jstor=1938060 |bibcode=1984Ecol...65..862J }}</ref> Due to the similarities of the foods and their aggressive dispositions towards one another, these ''Buteos'' need some degree of partitioning to persist alongside one another and this usually is given by habitat preferences. The ferruginous hawk prefers open, practically treeless [[prairie]] while of these, the red-tailed hawks prefers the most wooded areas with large trees, while the Swainson's hawk prefer roughly intermediate areas.<ref name="Restani" /><ref name="Janes" /><ref name="Schmutz" /> Where the habitat is more open, such as in [[Cassia County, Idaho]], the Swainson's and ferruginous hawks have the advantage in numbers and red-tails are scarce.<ref>{{cite journal|author=Thurow, T. L., & White, C. M. |year=1983|url=https://sora.unm.edu/node/51055|title=Nest site relationship between the ferruginous hawk and Swainson's hawk|journal= Journal of Field Ornithology|volume= 54|issue=4|pages= 401–406|jstor=27639274}}</ref> However, habitat alterations by humans, such as fire suppression and recovering pasture, usually favor the red-tailed hawk and are to the detriment of the other two species.<ref name="Johnsgard" /><ref>{{cite journal|author=Woffinden, N. D., & Murphy, J. R. |title=Decline of a Ferruginous Hawk Population: A 20-Year Summary|url=https://archive.org/details/sim_journal-of-wildlife-management_1989-10_53_4/page/1127 |journal=The Journal of Wildlife Management|volume=53|issue=4|pages=1127–1132|doi=10.2307/3809619|jstor=3809619|year=1989}}</ref><ref name="Trees" /> These practices have caused range expansions of many other species of birds but declines in many others.<ref>{{cite journal|author=Livezey KB|year= 2009|title=Range expansion of Barred Owls, part I: chronology and distribution|url=https://archive.org/details/sim_american-midland-naturalist_2009-01_161_1/page/49|journal= American Midland Naturalist |volume=161|issue= 1|pages=49–56|jstor=20491416|doi=10.1674/0003-0031-161.1.49|s2cid= 86276981}}</ref><ref>{{cite journal|author=Livezey KB|year= 2009|title=Range expansion of Barred Owls, part 2: facilitating ecological changes|url=https://archive.org/details/sim_american-midland-naturalist_2009-04_161_2/page/323|journal= American Midland Naturalist |volume=161|issue= 2|pages=323–349|jstor=20491442|doi=10.1674/0003-0031-161.2.323|s2cid= 84426970}}</ref><ref>{{cite journal|author=Livezey KB|year= 2010|title= Killing barred owls to help spotted owls II: implications for many other range-expanding species|journal= Northwestern Naturalist |volume=91|issue= 3|pages=251–270|jstor=40983223|doi=10.1898/NWN09-38.1|s2cid= 85425945}}</ref> Of these three ''Buteo'' species, the Swainson's hawk is most dissimilar, being a long-distance migrant which travels to South America each winter and, for much of the year, prefers to prey on insects (except for during breeding, when more nutritious food such as [[ground squirrel]]s are mainly fed to the young). It also breeds notably later than the other two species.<ref>England, A. S., Bechard, M. J., & Houston, C. S. (1997). ''Swainson's hawk''. American Ornithologists' Union.</ref> Surprisingly, although it's slightly smaller in body mass and has notably smaller (and presumably weaker) feet than ferruginous and red-tailed hawks, the Swainson's is actually usually (but not invariably) dominant in territorial conflicts over the other two. Part of this advantage is that the Swainson's hawk is apparently a superior flier both in long and short-distance flights, with its more pointed wing shape and lower wing loading allowing it more agile, sustained and speedier flight that the bulkier hawks cannot match.<ref name="Swainson">{{citation |last=Janes |first=S.W. |year=1985 |title=Interspecific interactions among grassland and shrubsteppe raptors: The smaller species wins |quote=Behavioral interactions and habitat relations among grassland and shrubsteppe raptors |page=7 }}</ref>{{full citation|date=July 2024|reason=Jounal? Report? Thesis? Publisher? Journal name?}} Therefore, in north-central [[Oregon]], Swainson's hawks were shown to be more productive, in prairie located trees, and partially displaced prior-breeding red-tails several times, although overall breeding success rates were not perceptibly decreased in the latter hawk.<ref name="Janes" /><ref>{{cite journal|author=Janes, S. W. |title=Partial Loss of Red-Tailed Hawk Territories to Swainson's Hawks: Relations to Habitat|journal=The Condor|volume=96|issue=1|pages=52–57|doi=10.2307/1369063|url=https://sora.unm.edu/node/104821|jstor=1369063|year=1994|url-access=subscription}}</ref> In the [[Chihuahuan Desert]] of [[Mexico]], Swainson's hawks usually nested in lowlands and red-tails nested in highlands but interspecies conflicts nevertheless were apparently quite frequent. Usually, the habitat preferences of red-tailed hawks and ferruginous hawks are discrepant enough to keep serious territorial conflicts to a minimum.<ref name="Steenhof2" /><ref name="Janes" /> However, red-tailed hawks and ferruginous hawks occasionally engaged in [[kleptoparasitism]] towards one another, usually during winter. Red-tails may be somewhat dominant based on prior reports in food conflicts but the ferruginous hawk may also win these.<ref name="CRPreston" /> Where they overlap, the hawk species may adjust their daily routine to minimize contact, which tends to be costly of time and energy and may cause the hawks to abandon their nests for long stretches of time, which in turn leaves their young vulnerable to predation.<ref name="Palmer" /> When habitats change rapidly, often due to human interference, and they nest more closely than natural partitioning would allow, in all three nesting success can decline significantly.<ref name="Schmutz" /> Beyond the Swainson's and ferruginous hawks, six other ''Buteos'' co-occur with red-tailed hawks in different parts of North America. Many of these are substantially smaller than red-tails and most serious territorial conflicts with them are naturally mitigated by nesting in deeper wooded areas.<ref name="Bent" /><ref name="Johnsgard" /> One other larger species, the [[rough-legged buzzard]], mostly nests far north of the breeding range of red-tailed hawks. However, in [[Alaska]] they sometimes nest in the same areas. The rough-legged buzzards are both cliff and tree nesters and areas used by the two species are not necessarily mutually exclusive but each seems to avoid the other, in part by differing breeding schedules.<ref>{{cite report |last=Mindell |first=D.P. |year=1983 |title=Nesting raptors in southwestern Alaska: Status, distribution, and aspects of biology |series=Alaska Technical Report |number=8 |place=Anchorage, AK |publisher=[[Bureau of Land Management]] }}</ref> Wintering rough-legged buzzards may regularly come into conflict over food with red-tailed hawks and seem to be subordinate to the red-tails, with several records of them being chased off both kills and carrion by the red-tailed hawks. During winter their hunting habits may keep them somewhat separate, the rough-legged being a much more aerial hunter, but rough-legged buzzards usually withdrew if a red-tailed hawk flew towards them. There is at least one case, however, of a rough-legged buzzard being the victor of a conflict over a kill with a red-tailed hawk.<ref name="Lowe" /><ref name="Bildstein" /> Red-tailed hawks are conspicuously more aggressive and tend to be dominant over slenderer, medium-sized ''Buteos'' such as [[red-shouldered hawk]]s and [[zone-tailed hawk]]s (''Buteo albonotatus'').<ref name="Brown" /> In [[Massachusetts]], red-shoulder hawks used mixed forests and hardwoods as nesting habitat while red-tails most often used in pitch pine and stunted oaks on [[Cape Cod]]. Nesting range overlap here most often occurred on [[white pine]] forests. As habitat has opened over time, red-tailed hawks frequently took over former red-shouldered hawk territories, even using their nests in two cases.<ref name="Palmer" /><ref name="Bent" /> In north-central Florida, it was found during winter that red-shouldered and red-tailed hawk habitat usage blurred and, because the local habitat favors red-shouldered hawks, they easily outnumbered the number of red-tailed hawks in the area. Therefore, again with sufficient habitat partitioning, the two species can live near one another without negatively effecting one another.<ref>{{cite journal|author=Bohall, P. G., & Collopy, M. W. |year=1984|title=Seasonal abundance, habitat use, and perch sites of four raptor species in north-central Florida|journal =Journal of Field Ornithology|volume=55|url=https://sora.unm.edu/node/51091|pages= 181–189}}</ref> In the [[American southwest]] and [[Texas]], two relatively large buteonine hawks also live alongside red-tailed hawks, the [[Harris's hawk]] (''Parabuteo unicinctus'') and the [[white-tailed hawk]] (''Geranoaetus albicaudatus''). Usually, habitat preferences kept conflicts to a minimum, with the red-tailed hawk favoring taller, more isolated saguaro cactus for nesting, whereas the other species outnumbered red-tails in areas that were denser and more shrubby.<ref name="Mader">{{cite journal|author=Mader, W. J. |year=1978|title=A comparative nesting study of red-tailed hawks and Harris' hawks in southern Arizona|journal= The Auk|volume=95|issue=2|pages= 327–337|doi=10.1093/auk/95.2.327|jstor=4085450|url=https://sora.unm.edu/node/23134|url-access=subscription}}</ref><ref>{{cite journal|author=Stevenson, J. O., & Meitzen, L. H. |year=1946|jstor=4157521|title=Behavior and food habits of Sennett's White-tailed Hawk in Texas|journal=The Wilson Bulletin|volume=58|issue=4 |pages= 198–205|url=https://sora.unm.edu/node/126715}}</ref> The Harris's hawk was determined to be a superior aerial hunter over red-tailed hawks, and could take down flying birds more routinely.<ref name="Mader" /> [[File:Kite on Hawk (50971162183).jpg|thumb|left|A [[white-tailed kite]] mobbing a red-tailed hawk.]] Hawks and [[Kite (bird)|kites]] from outside the buteonine lineage are usually substantially smaller or at least different enough in diet and habitat to largely avoid heavy conflict with red-tailed hawks. On occasion, [[northern harrier]]s (''Circus hudsonius'') which have much lower wing loading, will mob red-tailed hawks out of their home ranges but in winter the red-tails seem to be dominant over them in conflicts over food.<ref name= Bildstein/><ref>Bildstein, K. L. (1988). "Northern Harrier ''Circus cyaneus''". In ''Handbook of North American birds''. R. S. Palmer, ed. New Haven, CT: Yale Univ. Press. pp. 251–303</ref> Among ''[[Accipiter]]'' hawks, the most similar to the red-tailed hawk in diet and size is the [[American goshawk]]. In some areas, the prey species of these can be very similar and North American populations of goshawks take many more squirrels and leporids than their Eurasian counterparts do.<ref name= Doyle/><ref name= Kenward>{{cite book | title = The Goshawk | first = Robert | last = Kenward | year = 2006 | publisher = T & A D Poyser | location = London, UK | page = 274 | isbn = 978-0-7136-6565-9 | url = https://books.google.com/books?id=_tGnSRa0S6sC&pg=PA274}}</ref> It was found that the feet and striking force of hunting goshawks was more powerful than that of the red-tailed hawk, despite the red-tails being up to 10% heavier in some parts of North America.<ref name="Goslow" /> Therefore, wild goshawks can dispatch larger prey both on average and at maximum prey size, with some victims of female goshawks such as adult [[hare]]s and galliforms such as [[Wild turkey|turkey]] and [[Western capercaillie|capercaillie]] weighing up to or exceeding roughly {{convert|4000|g|lb|abbr=on}}.<ref>{{cite journal|author=Golet, G. H., Golet, H. T., & Colton, A. M. |year=2003|title=Immature Northern Goshawk captures, kills, and feeds on adult-sized wild turkey|url=https://sora.unm.edu/node/54064|journal=Journal of Raptor Research|volume= 37|issue=4|pages= 337–340}}</ref><ref>{{cite journal|author=Tornberg, R. |year=2001|title=Pattern of goshawk Accipiter gentilis predation on four forest grouse species in northern Finland|journal=Wildlife Biology|volume= 7|issue=4|pages=245–256|doi=10.2981/wlb.2001.029|s2cid=90797670|doi-access=free|bibcode=2001WildB...7..245T }}</ref><ref>{{cite journal|author=Tornberg, R., Mönkkönen, M., & Pahkala, M. |year=1999|title=Changes in diet and morphology of Finnish goshawks from 1960s to 1990s|url=https://archive.org/details/sim_oecologia_1999-11_121_3/page/369 |journal=Oecologia|volume= 121|issue=3|pages= 369–376|doi=10.1007/s004420050941|pmid=28308326|bibcode=1999Oecol.121..369T|s2cid=3217469}}</ref> In a comparative study in the [[Kaibab Plateau]] of [[Arizona]], however, it was found that red-tailed hawks had several population advantages. Red-tails were more flexible in diet, although there was a very broad overlap in prey species selected, and nesting habitat than the goshawks were.<ref name="Gatto" /> As red-tailed hawks in conflict with other more closely related ''Buteo'' hawks rarely (if ever) result in mortality on either side, goshawks and red-tailed hawks do seem to readily kill one another. Adults of both species have been shown to be able to kill adults of the other.<ref name="Luttich" /><ref name="Smithers2005">{{cite journal |last1=Smithers |first1=B.L. |last2=Boal |first2=C.W. |last3=Andersen |first3=D.E. |url=https://sora.unm.edu/node/54194|title=Northern Goshawk diet in Minnesota: An analysis using video recording systems |journal=Journal of Raptor Research |year=2005 |volume=39 |issue=3 |pages=264–273|bibcode=2005JRapR..39..264S }}</ref><ref>{{cite journal|author=Reynolds, R. T., Joy, S.M. & Leslie, D.G. |year=1994|title=Nest productivity, fidelity, and spacing of northern goshawks in northern Arizona|journal=Stud. Avian Biol.|volume=16|pages=106–113}}</ref><ref name="Boal">{{cite journal|author=Boal, C. W. |year=2005|title=Productivity and mortality of northern goshawks in Minnesota|journal=J. Raptor Res.|volume= 39|issue=3|pages= 222–228|bibcode=2005JRapR..39..222B |url=https://sora.unm.edu/node/54189}}</ref>{{Excessive citations inline|date=April 2023}} [[File:RTH-and-Mock-Chase-Wiki.jpg|thumb|A red-tailed hawk is mobbed by a [[northern mockingbird]] in the urban environment of [[Philadelphia]], Pennsylvania.]] The [[great horned owl]] occupies a similar [[ecological niche]] nocturnally to the red-tailed hawk.<ref name= Marti95/> There have been many studies that have contrasted the ecology of these two powerful raptors.<ref name= Craighead/><ref name= Orians/><ref name= Springer/> The great horned owl averages heavier and larger footed, with northern populations averaging up to 26% heavier in the owl than the hawk.<ref name= Craighead/> However, due in part to the red-tail's more extensive access to sizable prey such as ground squirrels, several contrasting dietary studies found that the estimated mean prey size of the red-tailed hawk, at {{convert|175|g|oz|abbr=on}}, was considerably higher than that of the great horned owl, at {{convert|76|g|oz|abbr=on}}.<ref name= Marti95/> Also, the diet of red-tailed hawk seems to be more flexible by prey type, as only just over 65% of their diet is made of mammals, whereas great horned owls were more restricted feeders on mammals, selecting them 87.6% of the time.<ref name= Sherrod/><ref name= Blumstein/><ref name= Voous>Voous, K.H. 1988. ''Owls of the Northern Hemisphere''. The MIT Press, 0262220350.</ref> However, the overall prey spectrum of great horned owls includes more species of mammals and birds (but far less reptiles) and the great horned owl can attack prey of a wider size range, including much larger prey items than any taken by red-tailed hawks. Mean prey weights in different areas for great horned owls can vary from {{convert|22.5|to|610.4|g|oz|abbr=on}}, so is far more variable than that of red-tailed hawks (at {{convert|43.4|to|361.4|g|oz|abbr=on}}) and can be much larger (by about 45%) than the largest estimated size known for the red-tailed hawk's mean prey weight but conversely the owl can also subsist on prey communities averaging much smaller in body size than can support the hawk.<ref name="Jaksic">Jaksić, F. M., & Marti, C. D. (1984). ''Comparative food habits of Bubo owls in Mediterranean-type ecosystems''. Condor, 288–296.</ref><ref name="Donazar">Donázar, J. A., Hiraldo, F., Delibes, M., & Estrella, R. R. (1989). ''Comparative food habits of the Eagle Owl Bubo bubo and the Great Horned Owl Bubo virginianus in six Palearctic and Nearctic biomes''. Ornis Scandinavica, 298–306.</ref> Some prey killed by great horned owls was estimated to weigh up to {{convert|6800|g|lb|abbr=on}}.<ref name="Sherrod" /><ref name="Voous" /><ref name="Cromrich">{{cite journal|author=Cromrich, L. A., Holt, D. W., & Leasure, S. M. |year=2002|title=Trophic niche of North American great horned owls|url=https://sora.unm.edu/node/53934|journal= Journal of Raptor Research|volume= 36|issue=1|pages= 58–65}}</ref> Great horned owls and red-tailed hawks compete not only for food but more seriously over nesting areas and home ranges. Great horned owls are incapable of constructing nests and readily expropriate existing red-tail nests. The habitat preferences of the two species are quite similar and the owl frequently uses old red-tail nests, but they do seem to prefer more enclosed nest locations where available over the generally open situation around red-tailed hawk nests. Sometimes in warmer areas, the owls may nest sufficiently early to have fledged young by the time red-tails start to lay. However, when there is a temporal overlap in reproductive cycles, the owl sometimes takes over an occupied red-tail nest, causing desertion. Red-tailed hawks have an advantage in staple prey flexibility as aforementioned, while great horned owl populations can be stressed when preferred prey is scarce, especially when they rely on leporids such as [[Snowshoe hare|hares]] and [[Black-tailed jackrabbit|jackrabbits]].<ref name="Palmer" /><ref name="Marti95" /><ref name="Doyle" /><ref name="Smith" />{{Excessive citations inline|date=April 2023}} For example, in [[Alberta]], when [[snowshoe hare]]s were at their population peak, red-tailed hawks did not increase in population despite taking many, with only a slight increase in mean clutch size, whereas the owls fluctuated in much more dramatic ways in accordance with snowshoe hare numbers. The red-tails migratory behavior was considered as the likely cause of this lack of effect, whereas great horned owls remained through the winter and was subject to winter-stress and greater risk of starvation.<ref name="McInvaille">McInvaille, W. B. (1972). ''Predator-prey relations and breeding biology of the great horned owl and red-tailed hawk in central Alberta''. University of Wisconsin-Madison.</ref> As a nester, great horned owl has the advantage in terms of flexibility, being somewhat spread more evenly across different habitats whereas in undisturbed areas, red-tailed hawks seem to nest more so in clusters where habitat is favorable.<ref name="Palmer" /><ref name="Orians" /><ref name="Springer" /><ref name="McInvaille" />{{Excessive citations inline|date=April 2023}} Predatory relationships between red-tailed hawks and great horned owls are quite one-sided, with the great horned owl likely the overall major predator of red-tails. On the other hand, red-tailed hawks are rarely (if ever) a threat to the great horned owl. Occasionally a red-tailed hawk can strike down an owl during the day but only in a few singular cases has this killed an owl.<ref>{{cite journal|author=Wilson, P.W. & Grigsby, E.M. |year=1980|title=Red-tailed Hawks Attack Great Horned Owl|journal=Inland Bird Banding|volume= 54|pages=80}}</ref><ref>{{cite journal|author=Smith, D. G. |year=1970|title=Close nesting and aggression contacts between Great Horned Owls and Red-tailed Hawks|url=https://sora.unm.edu/node/21968|journal= The Auk|volume= 87|issue=1|pages=170–171|doi=10.2307/4083679|jstor=4083679|url-access=subscription}}</ref> Most predation by the owls on the hawks is directed at nestlings at the point where the red-tails' nestlings are old enough that the parents no longer roost around the nest at night. Up to at least 36% of red-tailed hawk nestlings in a population may be lost to great horned owls.<ref name="Palmer" /><ref name="Luttich" /> Adult and immature red-tailed hawks are also occasionally preyed upon at night by great horned owls in any season. In one case, a great horned owl seemed to have ambushed, killed and fed upon a full-grown migrating red-tail even in broad daylight.<ref name="Palmer" /><ref name="Bent" /> Occasionally, both red-tails and great horned owls will engage each other during the day and, even though the red-tailed hawk has the advantage at this time of day, either may succeed in driving away the other.<ref name="CRPreston" /><ref name="Bent" /><ref name="McInvaille" /> Despite their contentious relations, the two species may nest quite close to one another. For example, in [[Saskatchewan]], the smallest distance between nests was only {{convert|32|to|65|m|ftin|0|abbr=on}}. In these close proximity areas all owl nests succeeded while only two red-tail nests were successful.<ref name="Houston">{{cite journal|author=Houston, C.S. |year=1975|title=Close proximity of Red-tailed Hawk and Great Horned Owl nests|journal=Auk |volume=92|issue=3|pages= 612–614|url=https://sora.unm.edu/node/22733|doi=10.2307/4084633|jstor=4084633|doi-access=free}}</ref> In [[Waterloo, Wisconsin]], the two species were largely segregated by nesting times, as returning red-tailed hawks in April–June were usually able to successfully avoid nesting in groves holding great horned owls, which can begin nesting activities as early as February.<ref name="Petersen">Petersen, L. (1979). [https://dnr.wi.gov/files/PDF/pubs/ss/SS0111.pdf ''Ecology of great horned owls and red-tailed hawks in southeastern Wisconsin (Technical Bulletin No. 111)'']. Department of Natural Resources.</ref> In [[Delaware County, Ohio]], and in central [[New York state]], divergence of hunting and nesting times usually allowed both species to succeed in nesting. In all three areas, any time the red-tails tried to nest closer to great horned owls, their breeding success rates lowered considerably. It is presumable that sparser habitat and prey resources increased the closeness of nesting habits of the two species, to the detriment of the red-tails. Due to nesting proximity to great horned owls, mature red-tails may have losses ranging from 10 to 26%.<ref name="Luttich" /><ref name="Springer" /><ref name="Houston" /><ref name="Hagar">{{cite journal|author=Hagar Jr., D. C. |year=1957|title=Nesting populations of red-tailed hawks and horned owls in central New York State|url=https://sora.unm.edu/node/127617|journal= The Wilson Bulletin|volume=69|issue=3 |jstor=4158602|pages= 263–272}}</ref>{{Excessive citations inline|date=April 2023}} Red-tailed hawks may face competition from a very broad range of predatory animals, including birds outside of typically active predatory families, carnivoran mammals and some reptiles such as snakes. Mostly these diverse kinds of predators are segregated by their hunting methods, primary times of activity and habitat preferences. In California, both the red-tails and [[western diamondback rattlesnake]]s (''Crotalus atrox'') live mainly on [[California ground squirrel]], but the rattlesnake generally attacks the squirrels in and around their burrows, whereas the hawks must wait until they leave the burrows to capture them.<ref>{{cite journal|author=Fitch, H. S.|title=Predation by Owls in the Sierran Foothills of California|journal=The Condor|volume=49|issue=4|pages=137–151|doi=10.2307/1364108|url=https://sora.unm.edu/node/99864|jstor=1364108|year=1947|url-access=subscription}}</ref> Hawks have been observed following [[American badger]]s (''Taxidea taxus'') to capture prey they flush and the two are considered potential competitors, especially in sparse sub-desert areas where the rodent foods they both favor are scarce.<ref>{{cite journal |author=Devers, Patrick K. |author2=Koenen, Kiana |author3=Krausman, Paul R. |name-list-style=amp |year=2004 |title=Interspecific interactions between badgers and red-tailed hawks in the Sonoran Desert, southwestern Arizona |journal=The Southwestern Naturalist |volume=49 |issue=1 |pages=109–111 |doi=10.1894/0038-4909(2004)049<0109:IIBBAR>2.0.CO;2 |jstor=3672278|s2cid=85752427 }}</ref> Competition over carcasses may occur with [[American crow]]s, and several crows, usually about six or more, working together can displace a hawk.<ref>{{cite journal |first=William|last= Langley |year=2001 |title=Competition between American crows and red-tailed hawks for a carcass: flock advantage |journal=[[Transactions of the Kansas Academy of Science]] |volume=104 |issue=1–2 |pages=28–30 |doi=10.1660/0022-8443(2001)104[0028:CBACAR]2.0.CO;2 |jstor=3628087|s2cid= 86701037 }}</ref> Another avian scavenger, the [[turkey vulture]] (''Cathartes aura''), is dominated by red-tails and may be followed by red-tails to supplant a carcass found by the vulture with their keen sense of smell.<ref>{{cite journal|author=Prior, K. A., & Weatherhead, P. J. |title=Competition at the carcass: Opportunities for social foraging by turkey vultures in southern Ontario|url=https://archive.org/details/sim_canadian-journal-of-zoology_1991-06_69_6/page/1550 |journal=Canadian Journal of Zoology|volume=69|issue=6|pages=1550–1556|doi=10.1139/z91-218|year=1991|bibcode=1991CaJZ...69.1550P }}</ref> In some cases, red-tailed hawks may be considered lessened as food competitors by their lack of specialization. For instance, no serious competition probably occurs between them and [[Canada lynx]] (''Lynx canadensis'') despite both living on snowshoe hares.<ref>Ruggiero, L. F., & Krebs, C. J. (1999). ''Habitat fragmentation and interspecific competition: implications for lynx conservation''. Ecology and conservation of lynx in the United States.</ref> [[File:Red-tailed Hawk with moon over Estero Bay CA - composition red-tail-moon-composite-2630s (323660913).jpg|thumb|Red-tailed Hawk with moon over Estero Bay CA]] Distinguishing territorial exclusionary behavior and anti-predator behavior is difficult in raptorial birds. However, as opposed to other medium to largish hawks which chase off red-tails most likely as competition, in much smaller raptors such as [[American kestrel|kestrels]] and smaller ''[[Accipiter]]'' hawks, their aggressive reaction to red-tailed hawks is almost certainly an anti-predator behavior. Although less prolific than [[American goshawk|goshawks]], some [[eagle]]s and, especially, [[great horned owl]]s, red-tailed hawks can and do prey upon smaller birds of prey. The following species of accipitrid have been known to fall prey to red-tailed hawks, potentially including nestlings, fledglings, immatures and/or adults: [[swallow-tailed kite]] (''Elanoides forficatus''),<ref>{{cite journal|author=Coulson, J. O., Coulson, T. D., DeFrancesch, S. A., & Sherry, T. W. |title=Predators of the Swallow-Tailed Kite in Southern Louisiana and Mississippi|journal=Journal of Raptor Research|volume=42|pages=1–12|doi=10.3356/JRR-07-08.1|year=2008|s2cid=84286796|doi-access=free}}</ref> [[Mississippi kite]] (''Ictinia mississippiensis''),<ref>{{cite journal|author=Miller, K. E. |year=2005|title=Red-tailed hawk depredates Mississippi kite nestling at dawn|journal= Journal of Raptor Research|volume= 39|issue=1|pages=108|url=https://sora.unm.edu/node/54166}}</ref> [[white-tailed kite]] (''Elanus leucurus''),<ref>{{cite journal|author=Pinkston, D.R. & Caraviotis, J.G. |year=1980|title=Probable predation on White-tailed Kite by Red-tailed Hawk|url=https://sora.unm.edu/node/52752|journal= Raptor Research |volume=14|pages= 85–86}}</ref> [[northern harrier]] (''Circus hudsonius''),<ref name= Blumstein/> [[sharp-shinned hawk]] (''Accipiter striatus''),<ref>{{cite journal|author=Klem, D., Hillegass, B. S., & Peters, D. A. |year=1985|jstor=4162078|title=Raptors killing raptors|journal=The Wilson Bulletin|volume= 97|issue=2|pages= 230–231|url=https://sora.unm.edu/node/130274}}</ref> [[Cooper's hawk]] (''Accipiter cooperii''),<ref>{{cite journal|url=https://sora.unm.edu/node/99626|author=Peyton, S. B. |title=From Field and Study |journal=The Condor |volume=47 |issue=4 |pages=167–173 |doi=10.2307/1364172|jstor=1364172 |year=1945 |url-access=subscription }}</ref> [[American goshawk|goshawks]],<ref name= Boal/> [[gray hawk]] (''Buteo plagiatus''),<ref>Bibles, Brent D., Richard L. Glinski and R. Roy Johnson. (2002). "Gray Hawk (''Buteo plagiatus''). In ''The Birds of North America''. {{doi|10.2173/bna.652}}.</ref> [[red-shouldered hawk]]<ref>{{cite journal|author=Miller, S. J., Dykstra, C. R., Simon, M. M., Hays, J. L., & Bednarz, J. C. |title=Causes of Mortality and Failure at Suburban Red-Shouldered Hawk (''Buteo lineatus'') Nests|journal=Journal of Raptor Research|volume=49|issue=2|pages=152–160|doi=10.3356/0892-1016-49.2.152|year=2015|s2cid=86095339|doi-access=free}}</ref> and [[broad-winged hawk]] (''Buteo platypterus'').<ref>{{cite journal|author=Hengstenberg, D. W., & Vilella, F. J. |year=2005|title=Nesting ecology and behavior of Broad-winged Hawks in moist karst forests of Puerto Rico|journal=Journal of Raptor Research|volume= 39|issue=4|pages=404|bibcode=2005JRapR..39..404H |url=https://sora.unm.edu/node/54208}}</ref> These species range from the {{convert|135.7|g|oz|abbr=on}} sharp-shinned hawk, the smallest North American accipitrid, to the goshawk, which at {{convert|956|g|lb|abbr=on}} is nearly red-tailed hawk sized.<ref name="Boal" /> Additionally, there are records of red-tailed hawks hunting 9 species of owl, ranging in size from the {{convert|104.2|g|oz|abbr=on}} [[northern saw-whet owl]] (''Aegolius acadius'') to juveniles of the {{convert|1079|g|lb|abbr=on}} [[great gray owl]] (''Strix nebulosa'') and seemingly adults of the {{convert|717|g|lb|abbr=on}} [[barred owl]] (''Strix varia'').<ref name="Sherrod" /><ref name="Blumstein" /> Red-tails will also hunt [[falcon]]s including adult [[American kestrel]]s (''Falco sparverius'') and [[Merlin (bird)|merlin]]s (''Falco columbarius'') and presumed nestlings of the [[peregrine falcon]] (''Falco peregrinus'').<ref name="Blumstein" /><ref name="Bahm">{{cite journal|author=Bahm, M. A., & Sullivan, B. L. |title=Interspecific Depredation of Raptors by Red-Tailed Hawks (''Buteo jamaicensis'') on San Clemente Island, California|journal=The Southwestern Naturalist|volume=54|pages=85–87|doi=10.1894/MH-27.1|year=2009|issue=1 |bibcode=2009SWNat..54...85B |s2cid=86659975}}</ref><ref>Warkentin, I. G., N. S. Sodhi, R. H. M. Espie, Alan F. Poole, L. W. Oliphant and Paul C. James. (2005). "Merlin (''Falco columbarius''). In ''The Birds of North America''. {{doi|10.2173/bna.44}}.</ref> When hunting other raptorial birds, red-tailed hawks seem to ambush them from a perch, diving suddenly and unexpectedly upon spotting the quarry and tend to have the greatest success when the raptorial prey is distracted, such as those migrating on windy days, feeding on their own prey and tending to their nest.<ref name="Palmer" /><ref name="Boal" /><ref name="Bahm" /> [[File:Red-tailed hawk landing.jpg|thumb|At the end of an aggressive flight]] In turn, red-tailed hawks may engage in behavior that straddles territorial exclusion and anti-predator behavior to the two much larger raptors in North America which actively hunt, the [[eagle]]s. Red-tails are most commonly seen flying towards and aggressively displacing both flying [[bald eagle]]s (''Haliaeetus leucocephalus'') and [[golden eagle]]s (''Aquila chrysaetos''), but may also, to the contrary, unobtrusively duck down out of flight to an inconspicuous perch when an eagle is spotted. The behavioral variation is probably related to the activity of hawks, which may feel the need to protect their nests and food resources while actively breeding but are not usually willing to risk their lives in attacking an eagle while migrating or wintering. At times mobbing behavior of smaller raptors may cause both eagles to turn over and present their large talons to their attacker, which can be dangerous for the smaller hawk.<ref name= Palmer/><ref name= Fitch/><ref name= Janes/><ref>{{cite journal|author=Le Duc, P. V. |year=1970|title=Red-Tailed Hawk Attacks Bald Eagle|journal=The Auk|volume=87|issue=3 (July–September)|pages= 586|url=https://sora.unm.edu/node/22027|doi=10.2307/4083809|jstor=4083809|doi-access=free}}</ref>{{Excessive citations inline|date=April 2023}} [[File:Red-tailed Hawk imported from iNaturalist photo 354788544 on 5 December 2024.jpg|thumb|[[Leucism|Leucistic]] red tailed hawk]] Besides the great horned owl, the two eagle species are the only known animals known to regularly threaten red-tailed hawks of any age. In particular, the golden eagle is probably the greatest daytime threat to fledged immature and adult red-tails, as these have turned up in many dietary studies of the powerful eagle.<ref name= Sherrod/><ref>{{cite journal|author=Olendorff, R. R. |title=The Food Habits of North American Golden Eagles|url=https://archive.org/details/sim_american-midland-naturalist_1976-01_95_1/page/231 |journal=American Midland Naturalist|volume=95|issue=1|pages=231–236|doi=10.2307/2424254|jstor=2424254|year=1976}}</ref> Less efficient as a predator of red-tails, bald eagles nonetheless have been recording killing adults in some cases or, more often, depredating red-tailed hawk nests. On occasion, this may result in the bald eagle bringing the nestling red-tails to their own nest and, for some reason, not killing them. In some cases, the bald eagles inadvertently actually raise the nestling red-tails themselves and the baby red-tailed hawks may successfully fledge.<ref>{{cite journal|author=Watson, J. W., Davison, M., & Leschner, L. L. |year=1993|title=Bald eagles rear red-tailed hawks|journal=Journal of Raptor Research|volume= 27|issue=2|pages= 126–127|url=https://sora.unm.edu/node/53357}}</ref> In one case, a red-tailed hawk was observed to kill a bald eagle chick, whether this was predatory or competitive, it quickly abandoned the dead nestling after the eagle's parents returned.<ref>{{cite journal|author=Perkins D.W., Phillips, D.M. & Garcelon, D.K. |year=1996|title=Predation on a Bald Eagle nestling by a Red-tailed Hawk|url=https://sora.unm.edu/sites/default/files/journals/jrr/v030n04/p00249-p00249.pdf|journal=Journal of Raptor Research |volume=30|pages= 249}}</ref> On several tropical islands, which are often shared only with other hawks, owls and falcons of only medium or small size and typically lack larger raptors or carnivorans, the red-tailed hawk may be the largest native predator and will, in these cases, be considered the [[apex predator]].<ref>{{cite journal|author=Wetmore, A., & Lincoln, F. C. |title=Additional notes on the birds of Haiti and the Dominican Republic|journal=Proceedings of the United States National Museum|volume=82|issue=2966|pages=1–68|doi=10.5479/si.00963801.82-2966.1|year=1933|url=https://www.biodiversitylibrary.org/part/8994}}</ref><ref name="White">{{cite journal|author=White, J., Kennedy, L. M., & Christie, M. E.|year=2017|title=Do perceptions of the Red-tailed Hawk indicate a human-wildlife conflict on the island of la Gonave, Haiti?|journal=Singapore Journal of Tropical Geography|volume=38|issue=2|pages=258–268|doi=10.1111/sjtg.12189|bibcode=2017SJTG...38..258W }}</ref> Other than large birds of prey, extensive records of predation on red-tailed hawks is surprisingly poor, in spite of several populations recording nestlings and eggs disappearing through presumed acts of natural predation. The most likely major predator of eggs and nestlings that disappear is the [[raccoon]] which, during its nocturnal foraging, is a notorious enemy of nearly any kind of birds nest.<ref name="Palmer" /><ref name="CRPreston" /><ref>{{cite web |url=http://www.fcps.edu/islandcreekes/ecology/red-tailed_hawk.htm |title=Red-tailed Hawk, ''Buteo jamaicensis'' |work=Study of Northern Virginia Ecology |publisher=[[Fairfax County Public Schools]] |access-date=16 May 2011 |archive-date=6 January 2016 |archive-url=https://web.archive.org/web/20160106032547/http://www.fcps.edu/islandcreekes/ecology/red-tailed_hawk.htm |url-status=dead }}</ref> It is also known that unidentified large snakes, probably consisting of the same species that the red-tails so readily predate during broad daylight, will prey upon nestling red-tails.<ref>Rosen, P. C. (2000). [https://repository.arizona.edu/handle/10150/289117 ''A monitoring study of vertebrate community ecology in the northern Sonoran Desert, Arizona'']. Department of Ecology and Evolutionary Biology Doctorate thesis, University of Arizona.</ref> In California, [[common raven]]s were recorded preying on the downy young of red-tailed hawks.<ref name="Wiley">{{cite journal|author=Wiley, J. W. |year=1975|title=The nesting and reproductive success of Red-tailed Hawks and Red-shouldered Hawks in Orange County, California, 1973|doi=10.2307/1365782|jstor=1365782|url=https://sora.unm.edu/node/102465|journal= The Condor|volume=77|issue=2|pages= 133–139|url-access=subscription}}</ref> Other corvids, including [[blue jay]]s (''Cyanocitta cristata''), [[California scrub jay]]s (''Aphelocoma californica'') and [[crow]]s, are known to feed on eggs and small nestlings either when nest attendance is atypically low by the hawks or when they can successful harass the parent hawks via mobbing so severely that they temporarily leave the nest.<ref name="CRPreston" /><ref name="Brown" /><ref>{{cite journal|author=Seidensticker IV, J. C., & Reynolds III, H. V. |year=1971|title=The nesting, reproductive performance, and chlorinated hydrocarbon residues in the Red-tailed Hawk and Great Horned Owl in south-central Montana|jstor=4160137|journal=The Wilson Bulletin|volume=83|issue=4 |pages= 408–418|url=https://sora.unm.edu/node/128806}}</ref> [[Simulium|Blackflies]] (''Simulium canonicolum'') have been recorded as killing several red-tail chicks through blood loss.<ref>{{cite journal|author=Smith, R. N., Cain, S. L., Anderson, S. H., Dunk, J. R., & Williams, E. S. |year=1998|title=Blackfly-induced mortality of nestling red-tailed hawks|journal=The Auk|volume=115|issue=2 |pages= 368–375|url=https://sora.unm.edu/node/25921|doi=10.2307/4089195|jstor=4089195|doi-access=free}}</ref> There are also several cases of possible prey turning the tables on red-tailed hawks and either maiming or killing them. This is especially true of snakes, with some prey species of ''[[Pituophis]]'', ''[[Pantherophis]]'' and ''[[Coluber]]'' known to overpower and nearly kill, often the hawk survives only if by human intervention. Not infrequently prey such as [[coral snake]]s and [[rattlesnake]]s may succeed in killing red-tailed hawks with their venom, even if they themselves are also killed and partially consumed.<ref name= Fitch/><ref name= Guthrie/><ref>{{cite journal|author=Brugger, K. E. |title=Red-Tailed Hawk Dies with Coral Snake in Talons|journal=Copeia|volume=1989|issue=2|pages=508–510|doi=10.2307/1445456|jstor=1445456|year=1989}}</ref><ref>{{cite web |url= http://www.ansp.org/about/academy-news/archive/2013/September/snake-versus-hawk/ |title= Snake versus Hawk |author= Kaczmarczik, M. |publisher= Academic of Natural Sciences |access-date= 2018-01-08 |archive-date= 30 June 2017 |archive-url= https://web.archive.org/web/20170630174803/http://ansp.org/about/academy-news/archive/2013/September/snake-versus-hawk/ |url-status= dead }}</ref>{{Excessive citations inline|date=April 2023}} [[Peregrine falcon]]s are also known to kill red-tailed hawks that have come too close to their nests by stooping upon them.<ref name= Palmer/> ==Reproduction== [[File:Courting redtails.JPG|thumb|Territorial adult chasing away an immature red-tailed hawk]] ===Courtship and pre-laying behaviors=== Pairs either court for the first time or engage in courtship rituals to strengthen pre-existing pair bonds before going into the breeding. The breeding season usually begins in late February through March, but can commence as early as late December in [[Arizona]] and late January in [[Wisconsin]] or to the opposite extreme as late as mid-April as in [[Alberta]].<ref name= Preston/><ref name= Orians/><ref name= Luttich/><ref name= Mader/>{{Excessive citations inline|date=April 2023}} In this pre-nesting period, high-circling with much calling will occur. One or both members of a pair may be involved. The courtship display often involves dangling legs, at times the pair will touching each other's wings and male's feet may touch female's back, she may occasionally roll over and present talons. Food passes are rarely reported.<ref name="Ferguson-Lees" /><ref name="Preston" /><ref name="Lowe" /> High soaring occurs aseasonally. Circling above territory tends to be done noisily and conspicuously, helping insure against possible takeovers. Spring circling of a pair can be a prelude to copulation.<ref name="Brown" /> A typical sky-dance involves the male hawk climbing high in flight with deep, exaggerated beats and then diving precipitously on half-closed wings at great speed, checking, and shooting back up, or often plunging less steeply and repeating process in a full rollercoaster across the sky. Sky-dances are done on periphery of the pair's territory and it appears to designate the territory limits, occasionally one male's sky-dance may also trigger a sky-dance by a neighboring male, who may even run a parallel course in the sky. Sky-dances no longer occur after late incubation.<ref name="Ferguson-Lees" /><ref name="Palmer" /><ref name="Bent" /> Boundary flight displays may be engaged in by all four birds of 2 adjacent pairs.<ref name="Brown" /> Cartwheeling with interlocking talons is also seen occasionally in spring, almost always a territorial male expelling an intruding one, the latter often being a second or third year male that is newly mature. A perched display, with fluffed-out breast feathers may too occur at this time. Even males that are in spring migration have been recorded engaging in a separate display: circling at slow speed before partially closing wings, dropping legs with talons spread and tilting from side-to-side. A female hawk is usually around when migrating male does this but she does not engage in this display herself.<ref name="Ferguson-Lees" /><ref name="Palmer" /> The area of occupancy of breeding territories by pairs is variable based on regional habitat composition. The highest recorded density of pairs was in California where each pair occurred on {{convert|1.3|km2|sqmi|abbr=on}}, which was actually just ahead of [[Puerto Rico]] where pair occupancy averaged {{convert|1.56|km2|sqmi|abbr=on}} in peak habitat. The largest known average territory sizes were surprisingly in [[Ohio]], where the average area of occupancy by pairs was recorded as {{convert|50|km2|sqmi|abbr=on}}.<ref name="Preston" /><ref name="Santana" /><ref name="Fitch" /> In [[Wisconsin]] mean ranges for males range from {{convert|1.17|to|3.9|km2|sqmi|abbr=on}} in males and from {{convert|0.85|to|1.67|km2|sqmi|abbr=on}} in females, respectively in summer and winter. Here and elsewhere, both members of the pair stay quite close together throughout winter if they are sedentary. On the other hand, migrant populations tend to separate while migrating and return to the same territory to find its prior mate, sometimes before they reach their home range.<ref name="Preston" /><ref name="Santana" /><ref name="Petersen" /> In [[Alaska]], returning migrant pairs were able to displace lone red-tailed hawks that had stayed on residence, especially lone males but sometimes even lone females.<ref name="Lowe" /> In general, the red-tailed hawk will only take a new mate when its original mate dies.<ref name="Terres">{{cite book | last =Terres | first =John K. | author-link =John Kenneth Terres | title =The Audubon Society Encyclopedia of North American Birds | publisher =Knopf | year =1980 | location =New York | page =[https://archive.org/details/audubonsocietyen00terr/page/1109 1109] | isbn =978-0-394-46651-4 | url-access =registration | url =https://archive.org/details/audubonsocietyen00terr/page/1109 }}</ref> Although pairs often mate for life, replacement of mates can often be quite fast for this common bird species. In one case in [[Baja California]], when a female was shot on 16 May, the male of that pair was seen to have selected a new mate the following day.<ref name="Palmer" /><ref>Anthony, A. W. (1893). ''Birds of San Pedro Mártir, Lower California''. Zoe 4: 228–247.</ref> In copulation, the female, when perched, tilts forward, allowing the male to land with his feet lodged on her horizontal back. The female twists and moves her tail feathers to one side, while the mounted male twists his cloacal opening around the female's cloaca. Copulation lasts 5 to 10 seconds and during pre-nesting courtship in late winter or early spring can occur numerous times each day.<ref name="Oiseaux">{{cite web|url=http://www.oiseaux.net/oiseaux/accipitriformes/red-tailed.hawk.html|title=''Buteo jamaicensis'' |publisher=Oiseaux.net |access-date=7 June 2007}}</ref> ===Nests=== [[File:4548 red tail hawk nest odfw (4438948012).jpg|thumb|left|Red-tailed hawks build large but untidy looking nests]] The pair constructs a stick [[bird nest|nest]] most often in a large tree {{convert|4|to|21|m|ft|abbr=on}} off the ground. They may too nest on virtually any man-made structures with some variety of ample ledges or surface space and good views of the surrounding environment (i.e. powerline poles, radio transmission towers, skyscraper buildings).<ref name= Preston/><ref name= Palmer/><ref name= Winn/><ref>{{cite journal|author=Stotz, N. |year=1994|title=Unusual nesting attempt by Red-tailed Hawk|journal= Kingbird |volume=44 |issue=3|pages=818–820|jstor=23324537}}</ref><ref>{{cite journal|author=Brubaker, D. L., K. L. Brubaker and B. C. Thompson|year=2003|title=Raptor and Chihuahuan Raven nesting on decommissioned telephone-line poles in the northern Chihuahuan Desert|journal=Journal of Raptor Research |volume=37 |issue=2|pages=135–146|url=https://sora.unm.edu/node/54030}}</ref><ref>{{cite journal|author=Pinel, H. W. and C. A. Wallis|year=1972|title=Unusual nesting records of Red-tailed Hawk in southern Alberta|journal=Blue Jay |volume=30|pages=30–31|doi=10.29173/bluejay3682|doi-access=free}}</ref>{{Excessive citations inline|date=April 2023}} Much variation is recorded in nest usage behavior, many red-tails build new nests every year despite prior nests sometimes being in good standing and unoccupied, some may reuse a nest in subsequent years or may leave a nest for a year and then come back to it the following year.<ref name="Preston" /><ref name="Palmer" /> A red-tailed hawk nest is typically located in a gradient zone between woods with tall, mature trees, if available, and openings whether this is composed of shrubland, grassland or agricultural areas.<ref>{{cite journal|author=Smith, R. N., Anderson, S. H., Cain, S. L., & Dunk, J. R. |year=2003|title=Habitat and nest-site use by Red-tailed Hawks in northwestern Wyoming|journal=Journal of Raptor Research|volume= 37|issue=3|pages= 219–227|url=https://sora.unm.edu/node/54044}}</ref> Nest sites vary greatly in topography and vegetative composition.<ref>Misztal, A. (1974). ''The population and nesting of Red-tailed Hawks and Great Horned Owls on the Wisconsin till plains of western Ohio''. Master's Thesis, Ohio State Univ., Columbus.</ref> While tree nests are largely preferred, occasionally they nest on [[cliff]] ledges may be used even where other nest sites are presumably available. Cliff nests may be located at {{Convert|35|m|ft|abbr = on}} or higher above the nearest flat ground.<ref name="Palmer" /><ref>Llerandi-Román, I. C., Rios-Cruz, J. M., & Vilella, F. J. (2009). ''Cliff-nesting by the Red-tailed Hawk in Moist Karst Forests of Northern Puerto Rico''. Journal of Raptor Research, 43(2), 167–169.</ref><ref>Coates, P. S., Howe, K. B., Casazza, M. L., & Delehanty, D. J. (2014). ''Landscape alterations influence differential habitat use of nesting buteos and ravens within sagebrush ecosystem: Implications for transmission line development''. The Condor: Ornithological Applications, 116(3), 341–356.</ref> At times, unlike [[great horned owl]]s, red-tailed hawks have been recorded nesting in surprisingly unbroken forests.<ref>{{cite journal|author=Titus, K., & Mosher, J. A. |year=1981|title=Nest-site habitat selected by woodland hawks in the central Appalachians|journal=The Auk|volume=98|issue=2 |jstor=4086065|pages= 270–281|url=https://sora.unm.edu/node/23532}}</ref> In [[North Dakota]], nest sites tend to be concentrated along wooded river drainages.<ref>{{cite journal|author=Gilmer, D. S., Konrad, P. M., & Stewart, R. E. |year=1983|title=Nesting ecology of Red-tailed Hawks and Great Horned Owls in central North Dakota and their interactions with other large raptors|journal=Prairie Naturalist|volume= 15|issue=3|pages= 133–143}}</ref> Compared to [[Swainson's hawk]]s and [[ferruginous hawk]]s, red-tailed hawk nests are usually in taller trees and are closer to waterways.<ref name="Schmutz" /><ref>Smith, D. G. (1971). ''Population dynamics, habitat selection, and partitioining of breeding raptors in the eastern Great Basin of Utah''. PhD diss., Brigham Young Univ., Provo, UT.</ref> In [[Puerto Rico]], nests are most often found in transitional zone between dry lowlands and mountainous cloud forests, with trees typically taller than their neighbors to allow views of more than half of their home ranges. More than 21 tree species were recorded used in Puerto Rico.<ref name="Santana" /> Tree species is seemingly unimportant to red-tailed hawks.<ref>Tietje, W. D., Bloom, P. H., & Vreeland, J. K. (1997). ''Characteristics of red-tailed hawk nest sites in oak woodlands of central California''. U S Forest Service General Technical Report PSW. no. 160 (December):365–372.</ref> In some parts of [[Arizona]], [[saguaro]] cactus were used exclusively as nesting sites.<ref name="Mader" /> Alternately, old nests of other ''[[Buteo]]'' hawks, [[corvid]]s, [[golden eagle]]s and even leaf nests of [[tree squirrel]]s have also been used by red-tailed hawks.<ref name="Ferguson-Lees" /> Both members of the pair will build the nests but the female spends more time forming the bowl, with the greatest activity often in the morning and nest building completed in 1 week or less.<ref name="Orians" /><ref name="Fitch" /> The nest is generally {{Convert|71|to|97|cm|abbr = on}} in diameter, with a mean of roughly {{convert|76|cm|in|abbr=on}}, and can be up to {{Convert|96|cm|in|abbr = on}} tall after several years use. The inner bowl averages about {{convert|37|cm|in|abbr=on}} wide and {{convert|13|cm|in|abbr=on}} deep.<ref name="Preston" /><ref name="Bent" /><ref name="Petersen" /> The nest is constructed of twigs, and lined with [[Bark (botany)|bark]], pine needles, [[corn cob]]s, husks, stalks, [[aspen]] catkins, or other plant lining matter. Lining the nest may be for warning other red-tails of the active use of a nest.<ref name="Preston" /><ref name="Orians" /> In moderate to northern climes, red-tailed hawks tend to face to the south or west, presumably to make them less vulnerable to strong northeasterly storm winds.<ref>{{cite thesis |last=Cornman |first=D.D. |year=1973 |title=Red-tailed hawk population ecology in Wood County, Ohio |degree=Master |publisher=[[Bowling Green State University]] |place=Bowling Green, OH }}</ref> ===Eggs=== In most of the interior [[contiguous United States]] the first egg is laid between mid-March and early April, ranging from 3–5 weeks after the nest is constructed, with the clutch completed 2–5 days after the initial egg is laid.<ref name= Preston/><ref>{{cite journal |last1=Luttich |first1=S.N. |last2=Keith |first2=L.B. |last3=Stephenson |first3=J.D. |year=1971 |title=Population dynamics of the Red-tailed Hawk (''Buteo jamaicensis'') at Rochester, Alberta |journal=[[The Auk]] |volume=88 |issue=1 |pages= 75–87 |doi=10.2307/4083962 |doi-access=free |jstor=4083962 |url=https://sora.unm.edu/node/22072 }}</ref> The average date of the laying the first egg can be variable: peaking mid-January in [[Puerto Rico]], averaging 9 March in [[Arizona]], 26 March in the [[Front Range Urban Corridor]] and 1 May in [[Alberta]].<ref name= Preston/><ref name= Santana/><ref name= Luttich/><ref name= Mader/>{{Excessive citations inline|date=April 2023}} The mean initiation of clutches may bump weeks later if {{convert|10|cm|in|abbr=on}} or more of snow is still on the ground in [[Wisconsin]] during March.<ref name= Orians/> A clutch of one to three [[egg]]s is laid in March or April, depending upon latitude, with four eggs being uncommon and five and perhaps even six increasingly rare.<ref name= Bent/> Clutch size depends almost exclusively on the availability of prey for the adults. At the species level, body size also determines clutch size. For example, while the total clutch weighs up to 18% of the females weight and the clutch size averages 2–3 eggs, a larger raptor like the [[golden eagle]] lays a smaller clutch, usually not more than two, that weighs less than 10% in total of the female's body mass, whereas a smaller raptor like the [[Eurasian kestrel|kestrel]] lays a larger clutch averaging five that weighs 50% of the females weight.<ref name="CRPreston" /> Average clutch sizes vary from 1.96 eggs in [[Alaska]] when prey populations were low up to 2.96 eggs in [[Washington (state)|Washington]].<ref name="Lowe" /><ref name="Henny">{{cite report |last1=Henny |first1=C.J. |last2=Wight |first2=H.M. |year=1972 |title=Population ecology and environmental pollution: Red-tailed and Cooper's hawks |number=2 |pages=229–250 |publisher=U.S. [[Fish and Wildlife Service]] }}</ref> Eggs are laid approximately every other day. Average egg sizes in height and width (each with a sample size of 20) are in the following subspecies- ''B. j. borealis'': {{convert|59.53|x|47.49|mm|in|abbr=on}}; ''B. j. calurus'': {{convert|60.04|x|47.1|mm|in|abbr=on}}; ''B. j. fuertesi'': {{convert|59.42|x|46.99|mm|in|abbr=on}}.<ref>{{cite book |last1=Baicich |first1=P.J. |last2=Harrison |first2=C. =J.O. |year=2005 |title=Nests, Eggs, and Nestlings of North American Birds |place=Princeton, NJ |publisher=Princeton University Press |page=480 |isbn=0691122954 }}</ref> The eggs of red-tailed hawks are mostly white, sometimes with a faint buffy wash; at times the eggs manifest a sparsely or heavily marked with blotches of buff, pale reddish-brown, dark brown, or purple. The markings often appear indistinctly and may combine to form a fine speckling.<ref>Harrison, H. H. (1979). ''A Field Guide to western bird's nests of 520 species found breeding in the United States west of the Mississippi River''. Boston, MA: A Field Guide to western birds' nests.</ref> They are [[Avian incubation|incubated]] primarily by the female, with the male substituting when she leaves to hunt or merely stretch her wings. Rarely do the males incubate more than four hours of daylight. The male brings most food to the female while she incubates.<ref name="Preston" /><ref name="Bent" /><ref name="Petersen" /><ref name="Wiley" />{{Excessive citations inline|date=April 2023}} ===Hatching, development, and brooding=== [[File:RT hawks.jpg|thumb|Parent in nest with chicks]] After 28–35 days of incubation (averaging about 3 days longer in the Caribbean as does fledgling as compared to North American red-tails), the eggs hatch over 2–4 days.<ref name=Ferguson-Lees/><ref>{{cite journal |last=Hardy |first=R. |year=1939 |title=Nesting habits of the western Red-tailed Hawk |journal=Condor |volume=41 |pages=79–80 |url=https://sora.unm.edu/node/98878 }}</ref> Like most raptorial birds, the nestlings are [[altricial]] and [[nidicolous]] at hatching.<ref name= Preston/><ref name=Fitch/> Hatchlings average {{convert|58|g|oz|abbr=on}} in body mass with no difference in sizes of the sexes until the young are about 29 days old for mass and 21 days or so for external linear standard measurements such as bill and talon size.<ref>{{cite journal |last1=Springer |first1=M.A. |last2=Osborne |first2=D.R. |name-list-style=amp |hdl=1811/22901 |year=1983 |title=Analysis of growth of the red-tailed hawk |journal=Ohio J. Sci. |volume=83 |pages=13–19 }}</ref> The female broods them while the male provides most of the food to the female and the young, which are also known as eyasses (pronounced "EYE-ess-ez"). The female feeds the eyasses after tearing the food into small pieces. The young red-tails are active by the second day when they issue soft peeping calls, bounce, and wave continuously with their wings. By day 7, the bouncing and peeping begin to wane, and young start to peck at prey in their nest. Nestlings emit high whistling notes (usually in response to adults overhead) by day 10, sit up on tarsometatarsi by day 15, become aggressive toward intruders by day 16, strike out with talons and wings by day 21, begin to stretch wings and exercise regularly by day 30. After 42–46 days, the eyasses begin to leave the nest and tear apart prey for themselves.<ref name= Preston/><ref name= Fitch/> The amount of food brought to the nest daily varies considerably, based on brood size and prey availability. In [[Alberta]], an average of {{convert|410|to|730|g|oz|abbr=on}} is brought each day for 1 to 3 nestlings while in [[Washington (state)|Washington]], it was estimated a minimum of {{convert|520|g|lb|abbr=on}} per day for 1 surviving nestling and in [[Wisconsin]], an estimated {{convert|219|g|oz|abbr=on}} was needed for 1 nestling and {{convert|313|g|oz|abbr=on}} for 2.<ref name="Petersen" /><ref name="McInvaille" /><ref name="Stinson">{{cite journal|author=Stinson, C. H.|title=Weather-Dependent Foraging Success and Sibling Aggression in Red-Tailed Hawks in Central Washington|journal=The Condor|volume=82|issue=1|pages=76–80|doi=10.2307/1366788|url=https://sora.unm.edu/node/103033|jstor=1366788|year=1980}}</ref> Brooding is strenuous for parent red-tails and both members of the pair usually lose some weight, especially the female. Some females may lose over {{convert|100|g|oz|abbr=on}} between hatching and fledging.<ref name="Preston" /> During brooding the female may become aggressive to intruders, including humans. In the east, red-tailed hawk females rarely defend nests from humans but historically in California and quite often still in [[Alaska]], some female will dive repeatedly and "savagely", sometimes snapping off large branches in her temper, occasionally stunning herself or inadvertently knocking down her own youngster if it is attempting to fledge. Apparently, the less extensive prior exposure they have to humans may make mature females more aggressive towards humans near the nest.<ref name="Palmer" /><ref name="Brown" /><ref name="Lowe" /> Although development is asynchronical in most nests, [[runt]]ing may sometimes be recorded and even [[siblicide]] may occur, with the parents feeding the weaker, younger chicks less so and both the siblings and parents occasionally aggressively pecking the "runts" of the nest. Ultimately, the runt in such cases does not usually survive and may be either found crushed in the nest, discarded out of the nest after starvation or consumed by the parents or the siblings. However, as a whole, such killings are fairly rare and only occur when food supplies are extremely low, often this being in sync with poor spring weather (such as overly rainy or cold conditions).<ref name="Palmer" /><ref name="Hagar" /><ref name="Stinson" /> If there is too much food, such as [[California ground squirrel]]s in California, the parents will discard remains after a day or two since decomposition of their prey invites infection, other diseases and blood-sucking insects to the nest that may endanger the nestlings. However, after about 4 weeks, the female often stops discarding leftover prey and the increased presence of flies may form somewhat of a risk to disease in the young but may also merely get the young to leave the nest sooner.<ref name="Brown" /><ref name="Fitch" /> One nest in California had two females and one male attended to; the male performed his usual function but both females would brood and tend to the nest.<ref>{{cite journal|author=Wiley, J. W. |title=Three Adult Red-Tailed Hawks Tending a Nest|journal=The Condor|volume=77|issue=4|pages=480–482|doi=10.2307/1366096|url=https://sora.unm.edu/node/102542|jstor=1366096|year=1975|url-access=subscription}}</ref> Additionally, [[bald eagles]] have been recorded to occasionally adopt red-tail fledglings into their nests. As recorded in Shoal Harbor Migratory Bird Sanctuary located near Sydney, British Columbia, on 9 June 2017, a juvenile red-tailed hawk was taken by a pair of bald eagles back to their nest, whereupon the chick, originally taken as prey, was accepted into the family by both the parents and the eagles' three fledglings. After surviving 6 weeks among the eagles, the fledgling, nicknamed "Spunky" by birdwatchers, had successfully begun learning to hunt and fly, showing that the aggressive hawk was able to survive among a nest of much larger adoptive siblings.<ref>{{cite web|url=https://www.bbc.com/news/world-us-canada-40224776|title=Bald eagle adopts 'mortal enemy' baby hawk|date=9 June 2017|work=BBC}}</ref><ref>{{cite web|url=http://news.nationalgeographic.com/2017/07/red-tailed-hawk-adopted-by-bald-eagles-video-spd/|archive-url=https://web.archive.org/web/20170727134707/http://news.nationalgeographic.com/2017/07/red-tailed-hawk-adopted-by-bald-eagles-video-spd/|url-status=dead|archive-date=27 July 2017|title=Why This Young Hawk Thinks It's an Eagle|date=25 July 2017|work=National Geographic|access-date=4 April 2018}}</ref> ===Fledging and immaturity=== [[File:Red-tail hawk (Buteo jamaicensis) chick (14045509068).jpg|thumb|left|A red-tailed hawk chick peers out of its cliff nest]] Young typically leave the nest for the first time and attempt their first flights at about 42–46 days after hatching but usually they stay very near the nest for the first few days. During this period, the fledglings remain fairly sedentary, though they may chase parents and beg for food. Parents deliver food directly or, more commonly, drop it near the young. Short flights are typically undertaken for the first 3 weeks after fledgling and the young red-tails activity level often doubles. About 6–7 weeks after fledging, the young begin to capture their own prey, which often consists of insects and frogs that the young hawks can drop down to onto the ground with relative ease. At the point they are 15 weeks old, they may start attempts to hunt more difficult mammal and bird prey in sync with their newly developed skills for sustained flight, and most are efficient mammal predators fairly soon after their first attempts at such prey. Shortly thereafter, when the young are around 4 months of age, they become independent of their parents. In some extreme cases, juvenile red-tails may prolong their association with their parents to as long as they are half a year old, as was recorded in [[Wisconsin]].<ref name= Petersen/><ref name= CRPreston/><ref name= Johnson>{{cite journal|author=Johnson, S. J. |year=1973|title=Post-fledging activity of the Red-tailed Hawk|journal=Raptor Res.|volume=7|pages=43–48|url=https://sora.unm.edu/node/52556}}</ref><ref>{{cite journal|author=Johnson, S. J. |year=1986|title=Development of hunting and self-sufficiency in juvenile Red-tailed Hawks (''Buteo jamaicensis'')|journal=Raptor Res. |volume=20|pages=29–34|url=https://sora.unm.edu/node/52968}}</ref>{{Excessive citations inline|date=April 2023}} After dispersing from the parental territory, juveniles from several nests may congregate and interact in a juvenile staging area. Although post-fledgling siblings in their parents care are fairly social, they are rarely seen together post distribution from their parents range.<ref name="Preston" /><ref name="Geller">{{cite journal|author=Geller, G. A., & Temple, S. A. |year=1983|title=Seasonal trends in body condition of juvenile Red-tailed Hawks during autumn migration|jstor=4161808|journal=The Wilson Bulletin|volume=95|issue=3 |pages= 492–495|url=https://sora.unm.edu/node/130080}}</ref> Usually, newly independent young hawks leave the breeding area and migrate, if necessary, earlier than adults do, however the opposite was true in the extreme north of [[Alaska]], where adults were recorded to leave first.<ref name="Geller" /><ref>{{cite journal|author=Kessel, B., & Springer, H. K.|title=Recent Data on Status of Some Interior Alaska Birds|journal=The Condor|volume=68|issue=2|pages=185–195|url=https://sora.unm.edu/node/101511|doi=10.2307/1365717|jstor=1365717|year=1966|url-access=subscription}}</ref> Immature hawks in migratory populations tend to distribute further in winter than adults from these populations do.<ref>Brinker, D. F., & Erdman, T. C. (1985). "Characteristics of autumn Red-tailed Hawk migration through Wisconsin". In Proc. Hawk Migration Conf. Vol. 4, pp. 107–136.</ref> Immatures attempting to settle for the winter often are harassed from territory to territory by older red-tails, settling only in small, marginal areas. In some cases, such as near urban regions, immatures may be driven to a small pockets of urban vegetation with less tree cover and limited food resources. When a distant adult appears, immatures may drop from a prominent perch to a more concealed one.<ref name="Brown" /><ref name="Orians" /> In some cases, hungry immature red-tails have been recorded making attempts at hunting prey beyond their capacities, expending valuable energy, such as healthy adults of larger carnivorans such as [[coyote]]s (''Canis latrans''), foxes and [[American badger|badgers]] and healthy flying [[passerine]]s.<ref name="Palmer" /> There are some cases of red-tailed hawks, presumably younger than two years of age, attempting to breed, often with an adult bird of the opposite sex. Such cases have been recorded in [[Alberta]], [[Arizona]] and [[Wisconsin]], with about half of these attempts being successful at producing young.<ref name="Luttich" /><ref name="Gates" /><ref name="Henny" /><ref>Millsap, B. A. (1981). [https://archive.org/details/distributionalst00mill ''Distributional status of falconiformes in west central Arizona: with notes on ecology, reproductive success and management'']. US Bureau of Land Management, Phoenix District Office.</ref>{{Excessive citations inline|date=April 2023}} However, while adult plumage and technically sexual maturity is attained at two years old, many red-tails do not first successfully breed until they are around 3 years of age.<ref name="Preston" /> ===Breeding success and longevity=== [[File:20170614-OC-PJK-0418 (35262069466).jpg|thumb|A recent fledgling on the ground, probably making its early hunting attempts.]] Breeding success is variable due to many factors. Estimated nesting success usually falls between 58% and 93%.<ref name= Mader/><ref name= Hagar/> Nesting success rates are probably drive primarily by prey populations, regional habitat composition, competition levels with other red-tailed hawks, predation rates (often due to [[great horned owl]]s or perhaps [[raccoon]]s) and human disturbance levels.<ref name= Palmer/><ref name= Preston/><ref name= CRPreston/> In [[Oregon]] specifically, nesting success varied primarily based on "dispersion and density of perches" secondarily to ground squirrel abundance and whether the nest of other pairs red-tails was directly visible from a nest.<ref name= Janes/><ref>{{cite journal|author=Janes, S. W. |title=Fidelity to Breeding Territory in a Population of Red-Tailed Hawks|journal=The Condor|volume=86|issue=2|pages=200–203|doi=10.2307/1367041|url=https://sora.unm.edu/node/103448|jstor=1367041|year=1984|url-access=subscription}}</ref> Repeated disturbances at the nest early in the nesting cycle may cause abandonment of eggs or nestlings in some cases, but seemingly pairs are less likely to abandon the young later in the season in cases of human disturbance.<ref name="Palmer" /> 30% of nesting deaths in a study from [[Wisconsin]] were from nestlings falling to their death or the nest collapsing.<ref name="Petersen" /> In [[Puerto Rico]], habitat appeared to be the primary driver of breeding success, as in lowland pastures nesting success was 43% producing a mean number of fledglings of 1.5 whereas in cloud forest success was 34% producing a mean of 0.7 fledglings.<ref name="Santana" /> A modelling study in Puerto Rico showed that, apart from adult survival, nestling survival had the second greatest influence on population growth.<ref>{{Cite journal|last1=Gallardo|first1=Julio C.|last2=Vilella|first2=Francisco J.|last3=Colvin|first3=Michael E.|date=2019|title=A seasonal population matrix model of the Caribbean Red-tailed Hawk Buteo jamaicensis jamaicensis in eastern Puerto Rico|journal=Ibis|language=en|volume=161|issue=2|pages=459–466|doi=10.1111/ibi.12703|s2cid=92803722|issn=1474-919X}}</ref> In [[Wyoming]], 12 pairs on a 12 square mile tract produced an average of 1.4 young per pair.<ref name="Brown" /> In comparison, the mean number of fledglings was 0.96 in [[Michigan]], 1.36 in [[Montana]] and was 1.4 in the [[Appalachians]].<ref name="Craighead" /><ref name="Johnson" /><ref>{{cite journal|author=Janik, C. A. & Mosher, J.A. |year=1982|title=Breeding biology of raptors in the central Appalachians|journal=Raptor Res. |volume= 16|pages=18–24|url=https://sora.unm.edu/node/52806}}</ref> In [[Wisconsin]], the number of young successfully to fledge ranged from 1.1 to 1.8 from year to year probably depending on staple prey numbers.<ref name="Orians" /> The record lifespan in wild for a red-tailed hawk is 25 years and 5 months from banding studies. In comparison, lifespans of up to 29.5 years have been recorded in captivity.<ref name="Palmer" /> In the wild, other red-tailed hawks have lived for at least 25 years, for example, [[Pale Male]] was born in 1990, and in Spring 2014 was still raising eyasses.<ref name="Winn" /> However, of 5195 banded wild red-tailed hawks in one bander's recordings, only 31 were reported to have survived to 17 years of age and only 11 survived for 20 years.<ref>{{cite journal|author=Soucy Jr., L. J. |year=1995|title=Live recovery of a venerable raptor, a longevity record for the Red-tailed Hawk|journal=North American Bird Bander |volume= 20 |issue=1|pages=26}}</ref> The average mortality rate at 1 year of age for red-tails is 54% and thereafter is around 20% from banding sources.<ref name="Henny" /> The estimated average lifespan of red-tailed hawks who attain maturity, per Palmer (1988), was claimed as only 6 to 7 years.<ref name="Palmer" /> The main causes of mortality considered as electrocution on power lines, other collisions, shooting, consumption of poisoned baits set for other animals and collision with vehicles and other crafts. While most mortality of young red-tails is at least mainly due to natural causes, mortality of fledged or older red-tails is now mostly attributable to human killing, accidental or intentional, as well as flying into manmade materials.<ref name="Ferguson-Lees" /><ref name="Wiley" /><ref> {{cite journal|author=Keran, D. |year=1981|title=The incidence of man-caused and natural mortalities to raptors|journal=Raptor Res|volume= 15|pages=108–112|url=https://sora.unm.edu/node/52790}}</ref> Hawks in urban areas are threatened by the use of rat traps and poisoned bait to kill rodents. This generally consists of [[warfarin]] cookies which induce internal bleeding in rats and mice, and a hawk that ingests rodents who have consumed rat poison can itself be affected.<ref>[https://www.allaboutbirds.org/raptors-and-rat-poison/ "Raptors and Rat Poison"]. ''allaboutbirds.org''. 15 July 2015.</ref> Red-tailed hawks are also vulnerable to fatal bacterial infections include [[peritonitis]], [[myocarditis]], [[Granuloma|granulamotous]], [[sarcocystosis]] and [[Nontuberculous mycobacteria|mycobateriosis]] as well as some forms of viral infection, to which immature hawks especially, as they often have less access to coverage in poor weather conditions, are most vulnerable.<ref name="Preston" /> Neither this nor other ''[[Buteo]]'' hawks were found to be highly susceptible to long-term DDT egg-shell thinning due to being part, generally, of relatively short, terrestrial-based food chains.<ref name="CRPreston" /> == Relationship with humans == {{Hatnote|See also [[#Distribution and habitat|§ Distribution and habitat]], for habitat relationships to human settlement patterns.}} [[File:Red-tailed Hawk (falconry, Canada).jpg|thumb|A hawk at the Canadian Raptor Conservancy in Ontario, Canada]] === Use in falconry === The red-tailed hawk is a popular bird in [[falconry]], particularly in the United States where the sport of falconry is tightly regulated; this type of hawk is widely available and is frequently assigned to apprentice falconers.<ref>[http://www.coloradohawkingclub.com/Interested-In-Falconry Interested In Falconry]. Colorado Hawking Club</ref> Red-tailed hawks are highly tameable and trainable, with a more social disposition than all other falcons or hawks other than the [[Harris's hawk]].<ref>Beebe, Frank (1984). ''A Falconry Manual''. Hancock House Publishers, {{ISBN|0-88839-978-2}}.</ref> They are also long lived and fairly disease resistant, allowing a falconer to maintain a red-tailed hawk as a hunting companion for potentially up to two decades.<ref name= Beebe/> There are fewer than 5,000 falconers in the United States, so despite their popularity any effect on the red-tailed hawk population, estimated to be about one million in the United States, is negligible.<ref name="Federal Register">{{cite web|url=http://www.fws.gov/policy/library/05-2378.html|publisher=Department of the Interior: Fish and Wildlife Service|title=Migratory Bird Permits; Changes in the Regulations Governing Falconry; Notice of Intent To Prepare an Environmental Assessment for Falconry and Raptor Propagation Activities; Proposed Rule and Notice|access-date=14 June 2007 |archive-url = https://web.archive.org/web/20070311204705/http://www.fws.gov/policy/library/05-2378.html |archive-date = 11 March 2007}}</ref> Not being as swift as [[falcon]]s or [[accipiter]]s, red-tailed hawks are usually used to hunt small game such as rabbits and squirrels, as well as larger quarry such as [[hares]]. However, some individuals may learn to ambush game birds on the ground before they are able to take off and accelerate to full speed, or as they have fly into cover after a chase. Some have even learned to use a falcon-like diving stoop to capture challenging game birds such as pheasants in open country. In the course of a typical hunt, a falconer using a red-tailed hawk most commonly releases the hawk and allows it to perch in a tree or other high vantage point. The falconer, who may be aided by a dog, then attempts to [[Hunting#Methods|flush]] prey by stirring up ground cover. A well-trained red-tailed hawk will follow the falconer and dog, realizing that their activities produce opportunities to catch game. Once a raptor catches game, it does not bring it back to the falconer. Instead, the falconer must locate the bird and its captured prey, "make in" (carefully approach) and trade the bird off its kill in exchange for a piece of offered meat.<ref name= Beebe/><ref name="McGranaghan">{{cite book| last =McGranaghan| first =Liam J.| title =The Red-Tailed Hawk: A Complete Guide to Training and Hunting North America's Most Versatile Game Hawk.| publisher =Western Sporting Publications| year =2001| page =181| isbn =978-0-9709571-0-8}}</ref> <gallery widths="200px" heights="140px"> File:Lena Chang (41351815842).jpg|A trained red-tailed hawk working with a volunteer from the Ojai Raptor Center File:Red-tailed hawk, falconer's bird.jpg|A falconer's red-tailed hawk comes in for a landing </gallery> === Feathers and Native American use === The [[feather]]s and other parts of the red-tailed hawk are considered [[sacred]] to many [[indigenous people]] and, like the feathers of the [[bald eagle]] and [[golden eagle]], are sometimes used in religious ceremonies and found adorning the [[regalia]] of many [[Native Americans in the United States]]; these parts, most especially their distinctive tail feathers, are a popular item in the Native American community.<ref name="Pequot">{{Cite journal|url=http://www.pequotmuseum.org/Home/CrossPaths/CrossPathsSpring2003/TheSacredMessengers.htm|last=Collier|first= Julie|title=The Sacred Messengers|journal=Cross Paths|date=Spring 2003|volume=6|issue=1|archive-url=https://web.archive.org/web/20080124145720/http://www.pequotmuseum.org/Home/CrossPaths/CrossPathsSpring2003/TheSacredMessengers.htm |archive-date=24 January 2008 |url-status=dead}}</ref> As with the other two species, the feathers and parts of the red-tailed hawk are regulated by the [[eagle feather law]],<ref name="Title 50">{{cite web|url=http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&tpl=/ecfrbrowse/Title50/50cfr22_main_02.tpl|title=TITLE 50—Wildlife and Fisheries|publisher=Electronic Code of Federal Regulations (e-CFR)|access-date=20 June 2007|url-status=dead|archive-url=https://web.archive.org/web/20070610034613/http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&tpl=%2Fecfrbrowse%2FTitle50%2F50cfr22_main_02.tpl|archive-date=10 June 2007}}</ref> which governs the possession of feathers and parts of migratory birds.<ref name="Feathers">{{cite web|url=http://www.pequotmuseum.org/Home/CrossPaths/CrossPathsSpring2003/FeatherLaw.htm|last=Cook|first=Stephen|title=Feather Law|publisher=Mashantucket Pequot Museum|access-date=20 June 2007|archive-date=5 August 2012|archive-url=https://web.archive.org/web/20120805153601/http://www.pequotmuseum.org/Home/CrossPaths/CrossPathsSpring2003/FeatherLaw.htm|url-status=dead}}</ref> == Citations == {{reflist|25em}} ==Cited sources== *{{cite book |title=The Birds of North America |editor-last=Poole |editor-first=A.F. |publisher=Cornell Lab of Ornithology|place= Ithaca, NY, USA}} ==External links== {{Commons}} {{Wikispecies|Buteo jamaicensis}} {{Wikisource|Ornithological Biography/Volume 1/Red-tailed Hawk|"The Red-tailed Hawk" by John James Audubon}} {{Wikisource|Ornithological Biography/Volume 1/Black Warrior|"The Black Warrior, ''Falco Harlani''" by John James Audubon}} * [https://www.allaboutbirds.org/guide/Red-tailed_Hawk/ Red-tailed hawk Species Account] – Cornell Lab of Ornithology * [http://www.mbr-pwrc.usgs.gov/Infocenter/i3370id.html Red-tailed hawk – ''Buteo jamaicensis''] {{Webarchive|url=https://web.archive.org/web/20160106032548/http://www.mbr-pwrc.usgs.gov/Infocenter/i3370id.html |date=6 January 2016 }} – USGS Patuxent Bird Identification InfoCenter * [http://www.library.fordham.edu/whatsnew/hawks.html Red-tailed hawk Pictures] {{Webarchive|url=https://web.archive.org/web/20111201091647/http://www.library.fordham.edu/whatsnew/hawks.html |date=1 December 2011 }} at Fordham University * [http://n-a-f-a.com North American Falconers Association] * [http://www.birdwatching-bliss.com/hawk-photos.html Comparison of tails on adults & immature birds] * [http://www.dyesscreek.com/miscellaneous_pages/kriders.html Discussion of Krider's and Harlan's forms and identification issues] * [https://www.flickr.com/groups/birdguide/pool/tags/Buteo%20jamaicensis Photo Field Guide on Flickr] * [http://eol.org/pages/1049057/ "Red-tailed hawk" in ''The Encyclopedia of Life''] * {{InternetBirdCollection|red-tailed-hawk-buteo-jamaicensis|Red-tailed hawk}} * {{VIREO|Red-tailed+hawk|Red-tailed hawk}} ===Historical works=== * [[John James Audubon]]. (1831). [https://www.biodiversitylibrary.org/page/33239059 The Red-tailed Hawk] in ''Ornithological Biography'' vol. 1 , pp. 265–272 (also on WikiSource, see next below). ** [[John James Audubon]]. (1840). [https://www.biodiversitylibrary.org/page/40382980 The Red-tailed Buzzard] in ''The Birds of America'' vol. 1, pp. 32–38. [The 1840 edition appears to be a combination of the two companion works from the early 1830s: the plates from ''Birds of America'' and the descriptions from ''Ornithological Biography''.] * [[John James Audubon]]. (1831). [https://www.biodiversitylibrary.org/page/33239235 The Black Warrior] in ''Ornithological Biography'' vol. 1, pp. 441–443 (also on WikiSource, see next below). ** [[John James Audubon]]. (1840). [https://www.biodiversitylibrary.org/page/40382988 Harlan's Buzzard] in ''The Birds of America'' vol. 1, pp. 38–40. ===Live nest cameras=== * [https://www.allaboutbirds.org/cams/red-tailed-hawks/ Live nestcam at Cornell University] * [https://thecollege.syr.edu/alumni/nest-cam/ Live nestcam at Syracuse University] {{Subspecies of Red-tailed hawk}} {{Buteoninae}} {{Taxonbar|from=Q457471}} {{Authority control}} [[Category:Apex predators]] [[Category:Articles containing video clips]] [[Category:Birds described in 1788]] [[Category:Birds of North America]] [[Category:Birds of prey of North America]] [[Category:Birds of the Dominican Republic]] [[Category:Buteo]] [[Category:Falconry]] [[Category:Taxa named by Johann Friedrich Gmelin]]
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