Editing Common raven (section)

=== Feeding ===
[[File:Common Raven Nationalpark Bayerischer Wald 01.jpg|thumb|left|Feeding]]
Common ravens are [[omnivorous]] and highly [[Opportunism#Biological|opportunistic]]: their diet may vary widely with location, season and [[serendipity]].<ref name="Nogales">{{cite journal |last=Nogales |first=Manuel |author2=Hernández, Elizabeth C. |year=1997 |title=Diet of Common Ravens on El Hierro, Canary Islands |journal=Journal of Field Ornithology |volume=68 |issue=3 |pages=382–391 |url= http://sora.unm.edu/sites/default/files/journals/jfo/v068n03/p0382-p0391.pdf| access-date=2007-05-16}}</ref> For example, those foraging on [[tundra]] on the [[Arctic North Slope]] of [[Alaska]] obtained about half their energy needs from [[predation]], mainly of [[Microtus|microtine rodents]], and half by scavenging, mainly of [[caribou]] and [[Rock ptarmigan|ptarmigan]] carcasses.<ref name="Temple">{{cite journal |last=Temple |first=Stanley A. |date=March 1974 |title=Winter food habits of Ravens on the Arctic Slope of Alaska |journal=Arctic |volume=27 |issue=1 |pages=41–46 |url=http://pubs.aina.ucalgary.ca/arctic/Arctic27-1-41.pdf |access-date=7 November 2014 |doi=10.14430/arctic2851 |archive-date=24 May 2011 |archive-url=https://web.archive.org/web/20110524142532/http://pubs.aina.ucalgary.ca/arctic/Arctic27-1-41.pdf |url-status=dead }}</ref>
[[File:Common Raven, Marin County, CA, USA imported from iNaturalist photo 72128898.jpg|thumb|Holding a deer leg]]
In some places they are mainly [[scavenger]]s, feeding on [[carrion]] as well as the associated [[maggot]]s and [[carrion beetle]]s. With large-bodied carrion, which they are not equipped to tear through as well as birds such as the much larger and hook-billed [[vulture]]s, they must wait for the prey to be torn open by another predator or flayed by other means.<ref>{{cite journal |last=Nelson |first= A.L. |date=January 1934 |title=Some early summer food preferences of the American Raven in southeastern Oregon |journal=Condor |volume=36 |issue=1 |pages=10–15 |url=http://sora.unm.edu/sites/default/files/journals/condor/v036n01/p0010-p0015.pdf| access-date=2007-05-16 |doi=10.2307/1363515|jstor=1363515 }}</ref> They are also known to eat the afterbirth of [[Sheep|ewe]]s and other large mammals.<ref name="Corvus corax Common raven">{{cite web | url=https://animaldiversity.org/accounts/Corvus_corax/ | title=Corvus corax (Common raven) | website=[[Animal Diversity Web]] }}</ref> Plant food includes cereal grains, acorns, buds, berries and fruit.<ref name="Corvus corax Common raven"/> They prey on small [[invertebrate]]s, amphibians, reptiles, small mammals and birds.<ref>{{cite journal| last=Gaston| first=A.J.|author2=Elliot, R.D. | year=1996| title=Predation by Ravens ''Corvus corax'' on Brünnich's Guillemot ''Uria lomvia'' eggs and chicks and its possible impact on breeding site selection|journal=Ibis |volume=138| pages=742–748| doi=10.1111/j.1474-919X.1996.tb08831.x| issue=4| title-link=Thick-billed murre}}</ref> Ravens may also consume the undigested portions of animal faeces, and human food waste. They store surplus food items, especially those containing fat, and will learn to hide such food out of the sight of other common ravens.<ref name="Goodwin. p139"/> Ravens also raid the food caches of other species, such as the [[Arctic fox]].<ref>{{cite journal |last=Careau |first=Vincent |author2=Lecomte, Nicolas|author3=Giroux, Jean-François|author4=Berteaux, Dominique |date=January 2007 |title=Common ravens raid arctic fox food caches |journal=Journal of Ethology |volume=25 |issue=1 |pages=79–82 |doi=10.1007/s10164-006-0193-7|s2cid=23425485 }}</ref> They often associate with another canine, the [[wolf]], as a [[kleptoparasite]], following to scavenge wolf-kills in winter,<ref>{{cite journal |last=Stahler |first=Daniel |author2=Heinrich, Bernd |author3=Smith, Douglas |s2cid=53176223 |date=August 2002 |title=Common ravens, ''Corvus corax'', preferentially associate with grey wolves, ''Canis lupus'', as a foraging strategy in winter |journal=Animal Behaviour |volume=64 |issue=2 |pages=283–290 |doi=10.1006/anbe.2002.3047}}</ref> but also co-operatively, having been observed to lead hunting wolf packs to potential prey that only the ravens can see from the air.{{Citation needed|reason=Previous citation did not contain information about this claim|date=December 2024}} Ravens are regular predators at bird nests, brazenly picking off eggs, nestlings and sometimes adult birds when they spot an opportunity. They are considered perhaps the primary natural threat to the nesting success of the critically endangered [[California condor]], since they readily take condor eggs and are very common in the areas where the species is being re-introduced. On the other hand, when they defend their own adjacent nests, they may incidentally benefit condors since they chase [[golden eagle]]s out of the area that may otherwise prey upon larger nestling and fledging condors. Although condors recognise ravens as threats and will chase them away, their usual nest sites are poorly concealed from ravens; the reason is unknown, but it may be due to the condor's lower aerial manoeuvrability, or a holdover from times when condor populations were denser, nest sites more limiting, and ravens less abundant.<ref>{{cite journal |journal=The Condor |title=Nest-site Biology of the California Condor |first1=Noel F. R. |last1=Snyder |first2=Rob R. |last2=Ramey |first3=Fred C |last3=Sibley |volume=88 |issue=2 |pages=228–241 |url=http://sora.unm.edu/sites/default/files/journals/condor/v088n02/p0228-p0241.pdf |doi=10.2307/1368920 |year=1986|jstor=1368920 }}</ref>

[[File:Common raves landfill.jpg|thumb|Flock feeding at a garbage dump]]
Common ravens nesting near sources of human [[Food waste|garbage]] included a higher percentage of food waste in their diet, birds nesting near roads consumed more [[roadkill|road-killed]] [[vertebrate]]s, and those nesting far from these sources of food ate more [[arthropod]]s and plant material. [[Fledging]] success was higher for those using human garbage as a food source.<ref name="Kristan">{{cite journal |last=Kristan |first=William B. |author2=Boarman, William I.|author3=Crayon, John J. |date=March 2004 |title=Diet composition of common ravens across the urban-wildland interface of the West Mojave Desert |url=http://public.csusm.edu/wkristan/kristan_et_al_raven_diet.pdf |journal=Wildlife Society Bulletin |volume=32 |issue=1 |pages=244–253 |doi=10.2193/0091-7648(2004)32[244:DCOCRA]2.0.CO;2  |s2cid=29170244 }}</ref> In contrast, a 1984–1986 study of common raven diet in an agricultural region of southwestern [[Idaho]] found that cereal grains were the principal constituent of [[pellet (ornithology)|pellet]]s, though small mammals, grasshoppers, cattle carrion and birds were also eaten.<ref name="Engel">{{cite journal |last=Engel |first=Kathleen A. |author2=Young, Leonard S.  |date=May 1989 |title=Spatial and temporal patterns in the diet of Common Ravens in southwestern Idaho |journal=Condor |volume=91 |issue= 2|pages=372–378 |url=http://sora.unm.edu/sites/default/files/journals/condor/v091n02/p0372-p0378.pdf| access-date=2005-05-16 |doi=10.2307/1368316|jstor=1368316 }}</ref>

One behaviour is recruitment, where juvenile ravens call other ravens to a food bonanza, usually a carcass, with a series of loud yells. In ''[[Ravens in Winter]]'', [[Bernd Heinrich]] posited that this behaviour evolved to allow the juveniles to outnumber the resident adults, thus allowing them to feed on the carcass without being chased away.<ref name="Bernd89">{{cite book| last=Heinrich| first=Bernd| author-link=Bernd Heinrich| year=1989| title=Ravens in Winter| location=New York| publisher=Summit Books| isbn=978-0-671-67809-8| url=https://archive.org/details/ravensinwinter00hein}}</ref> A more mundane explanation is that individuals co-operate in sharing information about carcasses of large mammals because they are too big for just a few birds to exploit.<ref name="Heinrich, B. 1999 pp&nbsp;119–120">Heinrich, B. (1999). ''Mind of the Raven: Investigations and Adventures with Wolf-Birds'' pp. 119–120. New York: Cliff Street Books. {{ISBN|978-0-06-093063-9}}</ref> Experiments with baits however show that such recruitment behaviour is independent of the size of the bait.<ref>{{cite journal|title=Winter foraging at carcasses by three sympatric corvids, with emphasis on recruitment by the raven, ''Corvus corax''|journal=Behavioral Ecology and Sociobiology | doi=10.1007/BF00300349|volume =23| issue=3| year= 1988 | pages=141–156| last=Heinrich| first=Bernd|bibcode=1988BEcoS..23..141H |s2cid=10471307 }}</ref>

Furthermore, there has been research suggesting that the common raven is involved in seed dispersal. In the wild, the common raven chooses the best habitat and disperses seeds in locations best suited for its survival.<ref name="P. J. Ewins" />