Editing Common raven (section)

== Behaviour ==
[[File:Corvus corax 2405 (8964295344).jpg|thumb|Group of ravens gathered around dead member]]
Common ravens usually travel in mated pairs, although young birds may form [[Flock (birds)|flocks]]. Relationships between common ravens are often quarrelsome, yet they demonstrate considerable devotion to their families.<ref name=Oregon/>

=== Predation ===
Owing to its size, gregariousness and its defensive abilities, the common raven has few natural predators. Predators of its eggs and chicks include [[marten]]s, large [[owl]]s, and sometimes [[eagle]]s. Ravens are quite vigorous at defending their young and are usually successful at driving off perceived threats. They attack potential predators by flying at them and lunging with their large bills. Humans are occasionally attacked if they get close to a raven nest, though serious injuries are unlikely. There are a few records of large birds of prey taking ravens; more rarely, large mammalian predators such as [[lynx]]es, [[coyote]]s and [[cougar]]s have also attacked ravens. This principally occurs at a nest site and when other prey for the carnivores are scarce.

In North America, predators of ravens have reportedly included [[great horned owl]]s, [[American goshawk]]s, [[bald eagle]]s, [[golden eagle]]s and [[red-tailed hawk]]s. It is possible that the hawk species only attack young ravens; in one instance a [[peregrine falcon]] swooped at a newly fledged raven but was chased off by the parent ravens.<ref>{{cite thesis|author=Boal, C. W. |year=1993|title=Northern goshawk diets in ponderosa pine forests in northern Arizona|publisher=University of Arizona |type=Masters of Science Thesis}}</ref><ref>{{cite journal|author=Murie, O. J. |year=1940|title=Food habits of the northern Bald Eagle in the Aleutian Islands, Alaska|jstor=1363948|url=https://sora.unm.edu/node/99047|journal= Condor|pages= 198–202|volume=42|issue=4|doi=10.2307/1363948|url-access=subscription}}</ref><ref>{{cite journal|author=Olendorff, R. R. |year=1976|title=The food habits of North American golden eagles|jstor=2424254|journal= American Midland Naturalist|pages= 231–236|volume=95|issue=1|doi=10.2307/2424254}}</ref><ref>{{cite book|author=Young, L. S. |author2=Engel, K. A. |year= 1988|title=Implications of communal roosting by Common Ravens to operation and maintenance of Pacific Power and Light Company's Malin to Midpoint 500 kV transmission line|publisher= U.S. Dept. of the Interior, Bureau of Land Manage|place= Boise, ID}}</ref> Ravens wary around novel carrion sites, and in North America, have been recorded waiting for the presence of [[American crow]]s and [[blue jay]]s before approaching to eat.<ref name=adw/>

In [[Eurasia]], their reported predators include, in addition to golden eagles, [[Eurasian eagle-owl]]s, [[white-tailed eagle]]s, [[Steller's sea-eagle]]s, [[eastern imperial eagle]]s and [[gyrfalcon]]s.<ref>{{cite journal|author=Malafosse, J. |year=1985|title=Quelques données sur le Hibou grand-duc (''Bubo bubo'') dans le département de la Lozère de 1978 à 1984|journal= Le Grand-Duc|volume= 26|pages= 26–32|url=http://files.biolovision.net/www.faune-auvergne.org/userfiles/GDUC/Grand-Duc%2026%20(04).pdf }}</ref><ref>{{cite journal|author1=Wille, F. |author2=Kampp, K.  |name-list-style=amp |year=1983|title=Food of the white-tailed eagle ''Haliaeetus albicilla'' in Greenland|journal= Ecography |volume=6|issue=1|pages= 81–88 |doi=10.1111/j.1600-0587.1983.tb01068.x|bibcode=1983Ecogr...6...81W }}</ref><ref>{{cite book|author1=Utekhina, I. |author2=Potapov, E. |author3=McGrady, M. J. |name-list-style=amp |year=2000|chapter=Diet of the Steller's Sea Eagle in the northern Sea of Okhotsk|title=First Symposium on Steller's and White-tailed Sea Eagles in East Asia|place= Tokyo, Japan|publisher= Wild Bird Society of Japan |pages=71–92}}</ref><ref>{{cite journal|author1=Chavko, J. |author2=Danko, Š. |author3=Obuch, J. |author4=Mihók, J.  |name-list-style=amp |year=2007|title=The food of the Imperial Eagle (''Aquila heliaca'') in Slovakia|journal= Slovak Raptor Journal|volume= 1|issue=1 |pages= 1–18|doi=10.2478/v10262-012-0001-y|s2cid=85142585 |doi-access=free}}</ref><ref>{{cite journal|author=Jenkins, M. A. |year=1978|title=Gyrfalcon nesting behavior from hatching to fledging|jstor=4085502|url=https://sora.unm.edu/node/23099|journal= Auk |volume=95|issue=1|pages=122–127|doi=10.2307/4085502|url-access=subscription}}</ref> Because they are potentially hazardous prey for raptorial birds, raptors must usually take them by surprise and most attacks are on fledgling ravens.

=== Breeding ===
[[File:Ravens nest Lastef.jpg|thumb|Young on a nest – Hvítserkur, Iceland]]
[[File:Corvus corax tingitanus MHNT 232 HdB Djebel Messaad Algerie.jpg|thumb|Eggs of ''Corvus corax'']]
[[File:Korp - Common raven - (Corvus corax) - Ystad - 2025.jpg|thumb|A pair with 3–4 young on top of a high-voltage pylon in [[Ystad]].]]
Juveniles begin to court at a very early age, but may not bond for another two or three years. Aerial acrobatics, demonstrations of intelligence, and ability to provide food are key behaviours of courting. Once paired, they tend to nest together for life, usually in the same location.<ref name="Oregon">{{cite web |url=http://www.oregonzoo.org/Cards/BirdsOfPrey/commonraven.htm|title= Oregon Zoo Animals: Common Raven|access-date=2007-05-19 |work= Oregon Zoo| archive-url = https://web.archive.org/web/20070429120446/http://www.oregonzoo.org/Cards/BirdsOfPrey/commonraven.htm| archive-date = April 29, 2007}}</ref> Instances of non-monogamy have been observed in common ravens, by males visiting a female's nest when her mate is away.<ref name="Heinrich, B. 1999 pp&nbsp;119–120"/>

Breeding pairs must have a territory of their own before they begin nest-building and reproduction, and thus they aggressively defend a territory and its food resources. Nesting territories vary in size according to the density of food resources in the area.<ref name="Boarman_Heinrich"/> The nest is a deep bowl made of large sticks (up to 150 cm long and 2.5 cm thick<ref name="Snow"/>) and twigs, bound with an inner layer of roots, mud, and bark and lined with a softer material, such as [[deer]] fur. The nest is usually placed in a large tree or on a cliff ledge, or less frequently in old buildings or utility poles.<ref>[[#Savage|Savage]], p. 35</ref>

Females usually lay between four to six (rarely two to seven) pale bluish-green, brown-blotched eggs.<ref name="Snow"/> Incubation is about 18 to 21 days, by the female only. The male may stand or crouch over the young, sheltering but not actually [[brooding]] them.<ref>{{cite journal |last=Gwinner |first=Eberhard |date=April 1965 |title=Beobachtungen über Nestbau und Brutpflege des Kolkraben (''Corvus corax'' L.) in Gefangenschaft |journal=Journal of Ornithology |volume=106 |issue=2 |pages=145–178 |doi=10.1007/BF01793758|bibcode= |s2cid=22796437 |language=de}}</ref> The young [[fledge]] at 35 to 49 days, and are fed by both parents. They stay with their parents for another six months after fledging.<ref>[[#Goodwin|Goodwin]], p. 141</ref>

In most of their range, egg-laying begins in late January or February,<ref name="Snow"/> but it can be as late as April in colder climates such as [[Greenland]] and [[Tibet]]. In Pakistan, egg-laying takes place in December,<ref name="Helm"/> but in north Africa (subspecies ''C. c. tingitanus''), later than in Europe, in late March or early April.<ref name="Snow"/> Eggs and hatchlings are preyed on, rarely, by large [[hawk]]s and [[eagle]]s, large [[owl]]s, [[marten]]s and [[canid]]s. The adults, which are very rarely preyed upon, are often successful in defending their young from these predators, due to their numbers, large size and cunning.<ref name=adw>{{cite web |access-date=2008-06-03 |vauthors=Berg R, Dewey T |year=1999 |publisher=University of Michigan |url=http://animaldiversity.ummz.umich.edu/site/accounts/information/Corvus_corax.html |title=''Corvus corax''|work=Animal Diversity Web}}</ref> They have been observed dropping stones on potential predators that venture close to their nests.<ref>{{cite journal |journal=Condor |title=The apparent use of rocks by a raven in nest defense |first=Stewart W. |last=Janes |url=http://sora.unm.edu/sites/default/files/journals/condor/v078n03/p0409-p0409.pdf |volume=78 |issue=3 |pages=409 |year=1976 |access-date=2009-03-26 |doi=10.2307/1367704|jstor=1367704}}</ref>

Common ravens can be very long-lived, especially in captive or protected conditions; [[Ravens of the Tower of London|individuals at the Tower of London]] have lived for more than 40 years.<ref name="Boarman_Heinrich"/> Their lifespans in the wild are shorter, typically 10 to 15 years. The longest known lifespan of a [[bird ringing|ringed]] wild common raven was 23 years, 3 months,<ref name=euroring>{{cite web |url=http://www.euring.org/data_and_codes/longevity-voous.htm |title=European Longevity Records |publisher=European Union for Bird Ringing |access-date=5 April 2011}}</ref> which among passerines only is surpassed by a few Australian species such as the [[satin bowerbird]].<ref>[[Australian Bird and Bat Banding Scheme]] ''[http://www.environment.gov.au/cgi-bin/biodiversity/abbbs/abbbs-search.pl?taxon_id=378 Satin Bowerbird]''</ref>

=== 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" />

=== Intelligence ===
{{See also|Bird intelligence|Corvidae#Intelligence}}

The brain of the common raven is among the largest of any bird species. Specifically, their [[avian pallium|hyperpallium]] is large for a bird. They display ability in problem-solving, as well as other [[cognitive]] processes such as [[imitation]] and [[Insight phenomenology|insight]].<ref name=birdinblack/>
[[File:Old NIKE Missile radar dome with ravens.JPG|thumb|Dilapidated [[Project Nike|Nike Missile]] radar dome in Alaska with an evening roost]]
Linguist [[Derek Bickerton]], building on the work of biologist [[Bernd Heinrich]], has argued that ravens are one of only four known animals (the others being [[bee]]s, [[ant]]s, and humans) who have demonstrated [[Displacement (linguistics)|displacement]], the capacity to communicate about objects or events that are distant in space or time. Subadult ravens roost together at night, but usually forage alone during the day. However, when one discovers a large carcass guarded by a pair of adult ravens, the unmated raven will return to the roost and communicate the find. The following day, a flock of unmated ravens will fly to the carcass and chase off the adults. Bickerton argues that the advent of linguistic displacement was perhaps the most important event in the evolution of human language, and that ravens are the only other [[vertebrate]] to share this with humans.<ref>Bickerton, Derek (2009). ''Adam's Tongue''. Hill and Wang. {{ISBN|978-0-8090-2281-6}}</ref>

One experiment designed to evaluate insight and [[problem-solving]] ability involved a piece of meat attached to a string hanging from a perch. To reach the food, the bird needed to stand on the perch, pull the string up a little at a time, and step on the loops to gradually shorten the string. Four of five common ravens eventually succeeded, and "the transition from no success (ignoring the food or merely yanking at the string) to constant reliable access (pulling up the meat) occurred with no demonstrable [[trial-and-error]] learning." This supports the hypothesis that common ravens are 'inventors', implying that they can solve problems. Many of the feats of common ravens were formerly argued to be stereotyped innate behaviour, but it now has been established that their aptitudes for solving problems individually and learning from each other reflect a flexible capacity for intelligent insight unusual among non-human animals.<ref>{{cite journal |last=Heinrich |first=Bernd |year=1995 |title=An Experimental Investigation of Insight in Common Ravens (''Corvus corax'')|jstor=4089030|journal=The Auk|volume= 112|issue=4 |pages=994–1003 |url=http://sora.unm.edu/sites/default/files/journals/auk/v112n04/p0994-p1003.pdf |access-date= 2007-05-16|doi=10.2307/4089030}}</ref> Another experiment showed that some common ravens could intentionally deceive their conspecifics.<ref>{{cite journal|last1=Bugnyar|first1=Thomas|last2=Kotrschal|first2=Kurt|title=Leading a conspecific away from food in ravens (''Corvus corax'')?|journal=Animal Cognition|date=2004|volume=7|issue=2|pages=69–76|url=http://klf.univie.ac.at/fileadmin/user_upload/p_klf/Bugnyar_and_Kotrschal2004.pdf|doi=10.1007/s10071-003-0189-4|pmid=15069605|s2cid=6590368|url-status=dead|archive-url=https://web.archive.org/web/20150928155529/http://klf.univie.ac.at/fileadmin/user_upload/p_klf/Bugnyar_and_Kotrschal2004.pdf|archive-date=2015-09-28}}</ref>

A study published in 2011 found that ravens can recognise when they are given an unfair trade during reciprocal interactions with conspecifics or humans, retaining memory of the interaction for a prolonged period of time. Birds that were given a fair trade by experimenters were found to prefer interacting with these experimenters compared to those that did not.<ref>{{Cite journal|last1=Müller|first1=J. J. A.|last2=Massen|first2=J. J. M.|last3=Bugnyar|first3=T.|last4=Osvath|first4=M.|date=2017-06-01|title=Ravens remember the nature of a single reciprocal interaction sequence over 2 days and even after a month|url=https://www.sciencedirect.com/science/article/pii/S0003347217301161|journal=Animal Behaviour|language=en|volume=128|pages=69–78|doi=10.1016/j.anbehav.2017.04.004|s2cid=27527201 |issn=0003-3472|hdl=1887/76850|hdl-access=free}}</ref> Furthermore, ravens in the wild have also been observed to stop cooperating with other ravens if they observe them cheating during group tasks.<ref>{{Cite journal|last1=Massen|first1=Jorg J. M.|last2=Ritter|first2=Caroline|last3=Bugnyar|first3=Thomas|date=2015-10-07|title=Tolerance and reward equity predict cooperation in ravens (Corvus corax)|journal=Scientific Reports|language=en|volume=5|issue=1|pages=15021|doi=10.1038/srep15021|pmid=26442633 |pmc=4595729 |bibcode=2015NatSR...515021M |issn=2045-2322}}</ref>

Common ravens have been observed calling [[wolf|wolves]] to the site of dead animals. The wolves open the carcass, leaving the scraps more accessible to the birds.<ref name=birdinblack>{{cite web|url=https://www.pbs.org/wnet/nature/ravens/ravens.html |title=PBS Nature: The Bird in Black |access-date=2007-05-07 |publisher=[[PBS]] |url-status=dead |archive-url=https://web.archive.org/web/20080717192617/http://www.pbs.org/wnet/nature/ravens/ravens.html |archive-date=July 17, 2008 }}</ref> They watch where other common ravens bury their food and remember the locations of each other's food caches, so they can steal from them. This type of theft occurs so regularly that common ravens will fly extra distances from a food source to find better hiding places for food.<ref>{{cite web|url= http://www.gi.alaska.edu/ScienceForum/ASF14/1426.html|title= The Raven's Game of Hide and Seek|access-date= 2007-05-07|last= Rozell|first= Ned|work= Alaska Science Forum|publisher= Geophysical Institute, University of Alaska Fairbanks|archive-url= https://web.archive.org/web/20070611185753/http://gi.alaska.edu/ScienceForum/ASF14/1426.html|archive-date= 2007-06-11|url-status= dead}}</ref> They have also been observed pretending to make a cache without actually depositing the food, presumably to confuse onlookers.<ref>[[#Marzluff|Marzluff and Angell]], p. 230</ref>

Common ravens are known to steal and cache shiny objects such as pebbles, pieces of metal, and golf balls. One theory is that they hoard shiny objects to impress other ravens.<ref>[[#Marzluff|Marzluff and Angell]], p. 232</ref> Other research indicates that juveniles are deeply curious about all new things, and that common ravens retain an attraction to bright, round objects based on their similarity to bird eggs. Mature birds lose their intense interest in the unusual, and become highly [[neophobia|neophobic]].<ref>{{cite journal|doi=10.1007/s10211-002-0061-6|author1=Kijne, M.  |author2=Kotrschal, K |year=2002|title=Neophobia affects choice of food-item size in group-foraging common ravens (''Corvus corax'')|journal=Acta Ethologica|issue=1|pages= 13–18|volume=5|s2cid=39984855 }}</ref>

The first large-scale assessment of ravens' cognitive abilities suggests that, by four months of age, ravens do about as well as adult [[chimpanzee]]s and [[orangutan]]s on tests of [[causal reasoning]], [[Social learning in animals|social learning]], [[theory of mind]], etc.<ref>{{Cite journal |last1=Pika |first1=Simone |last2=Sima |first2=Miriam Jennifer |last3=Blum |first3=Christian R. |last4=Herrmann |first4=Esther |last5=Mundry |first5=Roger |date=2020-12-10 |title=Ravens parallel great apes in physical and social cognitive skills |journal=Scientific Reports |language=en |volume=10 |issue=1 |pages=20617 |doi=10.1038/s41598-020-77060-8 |pmid=33303790 |pmc=7728792 |bibcode=2020NatSR..1020617P |s2cid=228099688 |issn=2045-2322}}</ref>

=== Play ===
There has been increasing recognition of the extent to which birds engage in [[play (activity)|play]]. Juvenile common ravens are among the most playful of bird species. They have been observed to slide down snowbanks, apparently purely for fun. They even engage in games with other species, such as playing catch-me-if-you-can with wolves, otters and dogs.<ref>[[#Savage|Savage]], pp. 70–71</ref> Common ravens are known for spectacular aerobatic displays, such as flying in loops or interlocking talons with each other in flight.<ref>[[#Savage|Savage]], p. 76</ref><ref>Heinrich, B. (1999). ''Mind of the Raven: Investigations and Adventures with Wolf-Birds'' p. 290. New York: Cliff Street Books. {{ISBN|978-0-06-093063-9}}</ref>

They are also one of only a few wild animals who make their own toys. They have been observed breaking off twigs to play with socially.<ref>Heinrich, B. (1999). ''Mind of the Raven: Investigations and Adventures with Wolf-Birds'' p. 282. New York: Cliff Street Books. {{ISBN|978-0-06-093063-9}}</ref>