Editing Cooper's hawk (section)

==Behavior==
[[File:Cooper&#039;s Hawk bathing on a city street (47930519353).jpg|thumb|right|A young Cooper's hawk makes use of a large roadside puddle as a bath]]

Cooper's hawk is a typical ''Accipiter'' in all respects.<ref name= Ferguson-Lees/> This species tends to be active earlier in the morning than sharp-shinned hawks and [[Eurasian sparrowhawk]]s (''Accipiter nisus'') and is generally much more likely to be active in the morning than in the afternoon.<ref>Lang, S. D., Mann, R. P., & Farine, D. R. (2019). ''Temporal activity patterns of predators and prey across broad geographic scales''. Behavioral Ecology, 30(1), 172–180.</ref> These hawks may readily take to conifers to [[Bird#Resting and roosting|roost]], generally sleeping with their heads tucked in.<ref name= Ferguson-Lees/><ref name= Murphy/> During daylight hours, they tend to [[Preening (bird)|preen]] while sitting on a perch about 11 times a day, and may take about 1–20 minutes to do so.<ref name= Meng/> When attaining water to drink, Cooper's hawks appear to prefer to come to relatively secluded waterways.<ref>Stone, K., & Ramsey, A. (2014). ''Raptor Use of Water Sources as Documented via a Remote Camera Network''. Intermountain Journal of Sciences, 20(4), 110.</ref> In more [[arid]] regions, Cooper's hawks may seek out artificial [[body of water|bodies of water]] to drink from (especially in passage).<ref>Lynn, J. C., Rosenstock, S. S., & Chambers, C. L. (2008). ''Avian use of desert wildlife water developments as determined by remote videography''. Western North American Naturalist, 68(1), 107–112.</ref> Although a rare behavior, there are now several records of juvenile hawks of the species [[Prone position|proning]] wherein they lie on their backs along a branch (or rarely the ground), apparently as a form of [[Sunning (behaviour)|sunning]].<ref name= Sobolik>Rosenfield, R. N. & Sobolik, L.E. (2014). ''Proning behavior in Cooper's Hawks (Accipiter cooperii)''. Journal of Raptor Research, 48:294–297.</ref> Cooper's hawks may come to walk on ground to gather nesting materials as well as to hunt.<ref name= Rosenfield11>Rosenfield, R. N., Bielefeldt, J. & Cary, J. (1991). ''Copulatory and other pre-incubation behaviors of Cooper's Hawks''. Wilson Bulletin, 103:656–660.</ref> Cooper's hawks have a well-developed muscle mass that powers their flight, especially helping with acceleration during hunts and when carrying heavy prey. However, some other non-raptorial birds may have similar muscularity relative to their mass, such as the [[Canada goose]] (''Branta canadensis'') and even [[pied-billed grebe]]s (''Podilymbus podiceps''), and these ample muscle masses may be correlated with [[Bird migration|migratory]] (rather than hunting) behavior.<ref name= Marsh>Marsh, R. L. & Storer, R.W. (1981). ''Correlations of flight-muscle size and body mass in Cooper's Hawk: a natural analogue of power training''. Journal of Experimental Biology, 91:363–368.</ref> Cooper's hawks have been recorded as engaging in an exaggerated, [[nighthawk]]-like flight in non-courtship circumstances, such as during migration or by recent fledglings.<ref name= Layne/><ref>Berger, D. D. (1957). ''Peculiar type of flight in Cooper's Hawks''. Wilson Bulletin 69:110–111.</ref> During the late nesting stage, parent Cooper's hawks were recorded during daylight in Utah to engage in soaring flight 8.4% for males and 8.1% of the time for females with a further 6.4% and 2.8% of the time in different kinds of flights, perching the remainder of the time (about 2–6 minutes at each perch interspersed with brief flights).<ref name= Fischer/> Another study found 13.7% and 10.7% of daylight at this later breeding stage to be in flight, the rest of time perching, with occasional inactive perching spells of around 15–40 minutes. However, that inactivity could last up to 5 hours during heavy rainfall.<ref>Kennedy, P. L., & Gessaman, J.A. (1991). ''Diurnal resting metabolic rates of accipiters''. Wilson Bulletin, 103:101–105.</ref> Breeding adults generally engage in agonistic behavior when an interloper of their sex is present; 11 responses showed that males responses consisted 64% of the provocations, 9% of the time by females and both members 27% of the time.<ref name= Boal2>Boal, C. W. (2001). ''Agonistic behavior of Cooper's Hawks''. Raptor Research 35:253–256.</ref> Frequent aggressive interactions were recorded between females, often yearling and second year vs older females.<ref name= Lien>Lien, L. A., Millsap, B. A., Madden, K., & Roemer, G. W. (2015). ''Male brood provisioning rates provide evidence for inter‐age competition for mates in female Cooper's Hawks Accipiter cooperii''. Ibis, 157(4), 860–870.</ref> Cooper's hawk's threat display appears to consist of them lowering their heads, raising their "crest" (capital tract), stretching out their wings, spreading the tail and engaging in vocalizations.<ref name=BOW/> Stress levels, as indicated by a study of [[corticosterone]] levels, were considered quite high when hawks are being handled by researchers, particularly in males (indicating that they experience higher levels of stress than females).<ref>Rogers, H. M., Bechard, M. J., Kaltenecker, G. S., & Dufty, A. M. (2010). ''The adrenocortical stress response in three North American accipiters during fall migration''. Journal of Raptor Research, 44(2), 113–119.</ref> Cooper's hawk is subject to frequent [[Mobbing (animal behavior)|mobbing]] by various birds and some mammals, with good cause, but evidence shows that even main prey types like [[Jay (bird)|jays]] will sometimes shy away from engaging in full-fledged mobbing of a Cooper's, perhaps due to the risk in closely approaching this very agile predator, which can in an instant suddenly turn and kill a member of the mob. Therefore, less dangerous hawks such as ''Buteos'' are mobbed more vigorously than the more dangerous Cooper's. Many potential prey will confine their response to a hawk of this species to vocal scolding and/or attempt escape before an attack occurs.<ref>Hamerstrom, F. (1957). ''The influence of a hawk's appetite on mobbing''. The Condor, 59(3), 192–194.</ref><ref>Dahl, J. A., & Ritchison, G. (2018). ''Responses of Blue Jays (Cyanocitta cristata) to raptors that differ in predatory threat''. Avian Biology Research, 11(3), 159–166.</ref><ref>Commons, K. A. (2017). ''Mobbing behavior in Wild steller's jay (Cyanocitta stelleri)''. Thesis, Humboldt State University.</ref>

===Migration===
[[File:Cooper&#039;s Hawk (45354526355).jpg|thumb|The distinctive long-tailed, large headed form of Cooper's hawk in flight; short wings, seen when flapping, are also characteristic.]]

Like a majority of diurnal birds of prey in the [[Northern Hemisphere]], Cooper's hawk is a [[Bird migration|partial migrant]]. They tend to be most migratory in the north and largely to partially sedentary elsewhere.<ref name= Ferguson-Lees/><ref name= Palmer/> With individual exceptions, hawks of the species largely migrate out of nearly all of their range in southern Canada as well as cooler parts of the [[Pacific Northwest]], essentially all of [[Montana]] and northern parts of surrounding states, the [[Dakotas]] (but for southern [[South Dakota]]), the northern parts of the [[Great Lakes region|Great Lake]] states, northern New York and much of [[New England]].<ref name="iucn status 13 November 2021" /><ref name= Ferguson-Lees/> Despite being classed as sedentary, banding studies have revealed that many Cooper's hawks south of the typical migratory populations engage in some variety of seasonal winter movements.<ref name= Goodrich2>Goodrich, L. J., Farmer, C.J., Barber, D.R., & Bildstein, K.L. (2012). ''What banding tells us about the movement ecology of raptors''. Journal of Raptor Research, 46: 27–35.</ref> Migrants in the [[Florida Keys]] were determined via [[Stable isotope ratio|stable isotopes]] to have originated from [[mid-Atlantic states]] and the southeastern United States both (largely) south of the typical migratory range.<ref>Meehan, T. D., Lott, C. A., Sharp, Z. D., Smith, R. B., Rosenfield, R. N., Stewart, A. C., & Murphy, R. K. (2001). ''Using hydrogen isotope geochemistry to estimate the natal latitudes of immature Cooper's Hawks migrating through the Florida Keys''. The condor, 103(1), 11–20.</ref> While females in the urban areas of [[Tucson]] were sedentary (99%), about 6% of the females outside of the urban areas did not remain on their breeding grounds during winter.<ref name= Recruitment>Millsap, B. A. (2018). ''Female recruitment in an urban subpopulation of Cooper's Hawks (Accipiter cooperii) in central New Mexico''. PhD dissertation, New Mexico State University. Las Cruces, NM, USA.</ref> In [[British Columbia]], many adults are non-migratory but juveniles do tend to migrate.<ref name= Meehan>Meehan, T. D., Rosenfield, R. N., Atudorei, V. N., Bielefeldt, J., Rosenfield, L. J., Stewart, A. C., Stout, W.E. & Bozek, M. A. (2003). ''Variation in hydrogen stable-isotope ratios between adult and nestling Cooper's Hawks''. The Condor, 105(3), 567–572.</ref> From the Great Lakes region in particular, migrants appear to disperse in multiple directions to the south.<ref name= Palmer/><ref>Stout, W. E., Rosenfield, R.N. & Bielefeldt, J. (2008). ''Wintering location of a Wisconsin Cooper's Hawk and impact of digital photography on wildlife research''. Passenger Pigeon, 70: 373–379.</ref> Multi-directional movements, even to the north as well as potentially any other direction, are more common than previously thought in this and other migratory raptors, which has been previously described as "inefficient and indirect method of 'homing'".<ref>Mueller, H. C., & Berger, D. D. (1969). ''Navigation by hawks migrating in spring''. The Auk, 86(1), 35–40.</ref> However, reaching regions where appropriate habitat and prey is available is probably far more significant in seasonal movements to birds of prey than climatic concerns.<ref name= Palmer/><ref name= Hoffman2>Hoffman, S. W., Smith, J. P., & Meehan, T. D. (2002). ''Breeding grounds, winter ranges, and migratory routes of raptors in the mountain west''. Journal of Raptor Research, 36(2), 97–110.</ref> Fairly strong evidence has been found of habitual northbound migration by Cooper's hawks from [[Central California|Central]] and [[Southern California]], usually over fairly short distances, often less than {{convert|320|km|mi|abbr=on}}. However, the three longest distance movements from southern California were all northbound, i.e. {{convert|616|to|993|km|mi|abbr=on}}.<ref name= Meehan/><ref name= Bloom>Bloom, P. H., McCrary, M. D., Papp, J. M., & Thomas, S. E. (2017). ''Banding Reveals Potential Northward Migration of Cooper's Hawks from Southern California''. Journal of Raptor Research, 51(4), 409–416.</ref> Cooper's hawks originating from [[Northern California]] do generally migrate south, mostly wintering in Mexico though sometimes covering up to {{convert|1637|km|mi|abbr=on}} to Central America.<ref name= Bloom/> In [[Lansing, Michigan]], evidence has been found of individual Cooper's hawks being annually devoted to the same wintering grounds, presumably due to their high quality.<ref>Sanz, J. J., Moreno, J., Merino, S., & Tomas, G. (2004). ''Some Evidence of Winter Site Fidelity in Cooper's Hawks''. Iberia, 61, 187–196.</ref>

Migratory movements in the autumn are generally between late August to mid-October, peaking at the end of September and beginning of October in the [[Eastern United States|east]], but sometimes migration extend into November.<ref name= Palmer/><ref name= Mueller2>Mueller, H. C., Mueller, N. S., Berger, D. D., Allez, G., Robichaud, W., & Kaspar, J. L. (2000). ''Age and sex differences in the timing of fall migration of hawks and falcons''. The Wilson Bulletin, 214–224.</ref> Meanwhile, spring northward migration may be any time from the end of February to May, with the last ones leaving Mexico in April and very late individuals were passing over [[south Texas]] in late May.<ref name= Ferguson-Lees/><ref name= Palmer/> Generally, spring migration is more dispersed and less consistent than fall migration.<ref name=BOW/> There is evidence from the [[Great Lakes]] region that spring migration is occurring sooner due to [[Global warming|warming temperatures]] in recent years.<ref>Sullivan, A. R., Flaspohler, D. J., Froese, R. E., & Ford, D. (2016). ''Climate variability and the timing of spring raptor migration in eastern North America''. Journal of Avian Biology, 47(2), 208–218.</ref> Passage appears to be timed to coincide with that of their main prey, medium-sized birds.<ref name= Palmer/> In migration, first-year juveniles precede two-year-old hawks which themselves precede adults when moving south in fall. Furthermore, females of all ages tend to migrate sooner and spend longer in winter quarters than like-age males, the latter staying relatively north and traveling back again earlier.<ref name= Ferguson-Lees/><ref name= Mueller2/><ref name= Hull>Hull, J. M., Pitzer, S., Fish, A. M., Ernest, H. B., & Hull, A. C. (2012). ''Differential migration in five species of raptors in central coastal California''. Journal of Raptor Research, 46(1), 50–56.</ref> The sharp-shinned hawk (despite the even more dimorphic migration times between sexes) showed no strong difference in distance on migration between the sexes, unlike female Cooper's which sometimes can move considerably further than males.<ref name= Goodrich2/> At regular western migration sites, the average difference of passage timing for Cooper's hawks of the earlier females and later males of like-age was five days.<ref name= DeLong>DeLong, J., & Hoffman, S. W. (1999). ''Differential autumn migration of Sharp-shinned and Cooper's hawks in western North America''. The Condor, 101(3), 674–678.</ref> In the [[Marin Headlands]], migration of the sexes differed by 6 days in juvenile, first-year females and males and by 11 days in older females and males.<ref name= Hull/> Like other ''Accipiters'' (but unlike [[falcon]]s), Cooper's appear to not start moving until day is warmer and [[thermal]]s can be used.<ref name= Palmer/> During migration they favor [[mountain ridge]]s and [[coast]]lines, which coincide with migratory raptors routes in general.<ref name=BOW/> This species can seem to cross some bodies of water unlike most sharp-shinned hawks but seldom do so over wide bodies of water.<ref name= Palmer/> However, they have been seen to turn up in such oceanic vicinities as the [[Florida Keys]] and [[Cuba]], and so are capable of crossing larger than usual bodies of water.<ref name= Rodriguez-Santana/><ref>Hundley, M. H., & Hames, F. (1960). ''Birdlife of the lower Florida Keys''. Florida Audubon Society.</ref> It is thought that Cooper's hawks also avoid the [[Great Plains]] while migrating as well.<ref name="Mueller"/> Like many other raptors, Cooper's hawks favor strong [[Wind direction|northwesterly winds]] during autumn passage.<ref>Haugh, J. R. (1971). ''A STUDY OF HAWK MIGRATION AND WEATHER IN EASTERN NORTH AMERICA''.</ref><ref>Kerlinger, P. (1989). ''Flight Strategies of Migrating Hawks''. University of Chicago Press, Chicago, IL, USA.</ref>

At coastal migration sites like [[Cape May]], first year Cooper's hawks are far more regularly encountered than older individuals, with the juvenile Cooper's accounting for 92.7% of recorded individuals of the species (juveniles of various other raptor species also generally seem to favor coastal over montane migration when it is available).<ref>Clark, W. S. (1985). ''Migration of the Merlin along the coast of New Jersey''. Raptor Res, 19(2/3), 85–93.</ref><ref>Sutton, C., & Sutton, P. (2006). ''Birds and birding at Cape May''. Stackpole Books.</ref> In Cape May, Cooper's hawks are the third most commonly recorded raptor species in passage behind the sharp-shinned hawk and the [[American kestrel]] (''Falco sparverius'') but are far less than numerous in migration or in winter in the nearby [[Delaware Bay]]shore locations of [[New Jersey]] than various other raptor species.<ref name= Sutton>Sutton, C., & Kerlinger, P. (1997). ''The Delaware bayshore of New Jersey: a raptor migration and wintering site of hemispheric significance''. Journal of Raptor Research, 31, 54–58.</ref> In the [[Manzano Mountains]] and [[Goshute Mountains]], juvenile sharp-shinned hawks were roughly twice as numerous as juvenile Cooper's hawks but the number of adults seen passing through of the two species was roughly the same.<ref name= DeLong/> At the [[Hawkwatching|hawkwatch]] in [[Cedar Grove, Wisconsin]], Cooper's hawk was not among the most regular species, being the 6th most frequently most recorded species.<ref>Mueller, H. C., & Berger, D. D. (1961). Weather and fall migration of hawks at Cedar Grove, Wisconsin''. The Wilson Bulletin, 73(2), 171–192.</ref> In central and southwestern [[Idaho]], Cooper's hawk accounted for relatively few of the recorded raptors, i.e. 3.45% of 748 migrating raptors.<ref>Bates, K. K. (2001). ''Monitoring raptors during autumn migration in southwestern and southcentral Idaho''. Bureau of Land Management.</ref> A similarly low volume was observed relative to other bird of prey species in [[Yellowstone National Park]], where Cooper's was only the 9th most frequently observed out of 17 species and averaged only 50 hawks in passage over the course of autumn.<ref>Baril, L. M., Haines, D. B., Walker, L. E., & Smith, D. W. (2018). ''Autumn Raptor Migration in Yellowstone National Park, 2011–2015''. The Canadian Field-Naturalist, 131(4), 303–311.</ref> Nonetheless, Cooper's hawk was second only to sharp-shinned hawk as the most frequently recorded species seen migrating at nine major hawkwatchs throughout the western United States (and 1 in Canada) and, unlike the sharp-shinned, has shown a trend of increase in numbers overall in recent decades, despite some declines in numbers at [[Grand Canyon|Lipan Point]] and [[Bridger Range]].<ref name= Smith2>Smith, J. P., Farmer, C. J., Hoffman, S. W., Kaltenecker, G. S., Woodruff, K. Z., & Sherrington, P. F. (2008). ''Trends in autumn counts of migratory raptors in western North America. State of North America's birds of prey''. Series in Ornithology, 3, 217–251.</ref> Cooper's hawk was the 7th most often recorded raptor at four migration sites along the [[Gulf Coast]], being much more frequently identified in the site at [[Veracruz]], Mexico than the ones in the United States, but showed an annual stability of numbers that many of the more numerous raptors (including sharp-shinned hawks) in passage did not.<ref>Smith, J. P., Farmer, C. J., Hoffman, S. W., Lott, C. A., Goodrich, L. J., Simon, J., Riley, C. & Inzunza, E. R. (2008). ''Trends in autumn counts of migratory raptors around the Gulf of Mexico, 1995–2005''. State of North America's birds of prey. Series in Ornithology, 3, 253–277.</ref> Along the [[Blue Mountain (Pennsylvania)|Kittatinny Ridge]] in Pennsylvania, studied Cooper's hawks that were migrating from further north spent only 12% of the day actually migrating, devoting the remainder of their time to perching and hunting along their passage.<ref>Goodrich, L. J. (2005). ''Migrant raptor habitat use along the Kittatinny Ridge: a critical corridor for eastern flyway birds''. Harrisburg, PA: State Wildlife Grants-Program.</ref> [[Adipose tissue|Fat stores]] were measured to consist of 4–12% of the body mass of migrants, being higher in autumn than in spring, and higher on average in adults over younger hawks and in females over males.<ref>DeLong, J. P., & Hoffman, S. W. (2004). ''Fat stores of migrant Sharp-shinned and Cooper's Hawks in New Mexico''. Journal of Raptor Research, 38(2), 163–168.</ref> Migration speeds appear to be largely similar to those of other raptors, with average speeds of {{convert|33.6|to|88|km/h|mph|abbr=on}}, but one migrating from Colorado was recorded to cover about {{convert|26|km|mi|abbr=on}} per day.<ref name= Goodrich/><ref name= Broun>Broun, M. & Goodwin, B.V. (1943). ''Flight speeds of hawks and crows''. Auk, 60 :487–492.</ref> Typically Cooper's hawk migrate singly but sometimes can be seen in groups of two to five.<ref name= Meng/><ref name= Broun/> [[Flock (birds)|Flocking]] is not typically engaged in by raptors who migrate using powered flight, such as ''Accipiters'', falcons and [[Northern harrier|harrier]]s, but many ''[[Buteo]]'' hawks do form loose flocks.<ref name= Black>Black, R. W., & Borowske, A. (2009). ''The morphology, flight, and flocking behaviour of migrating raptors''. Evolutionary Ecology Research, 11(3), 413–420.</ref> 96.3% of 806 observed Cooper's hawk seen migrating in [[Johnson County, Iowa]] were solitary, although 30 migrating pairs were seen together.<ref name= Black/>