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Corvus coraxcommon raven

By Tanya Dewey and Rachel Berg

Ge­o­graphic Range

Com­mon ravens are one of the most wide­spread, nat­u­rally oc­cur­ring birds world­wide. They are found in north­ern Eu­rope, the British Isles, Green­land (mainly coastal areas), Ice­land, north­ern Scan­di­navia, east through cen­tral Asia to the Pa­cific Ocean and south to the Hi­malayas and north­west­ern India, Iran­ian re­gion and near east, north­west­ern Africa and the Ca­nary Is­lands, and North and Cen­tral Amer­ica as far south as Nicaragua. (Boar­man and Hein­rich, 1999)

Habi­tat

Com­mon ravens pre­fer open land­scapes, such as tree­less tun­dra, sea­coasts, open river­banks, rocky cliffs, moun­tain forests, plains, deserts, and scrubby wood­lands. How­ever, these ravens can be found in most types of habi­tats ex­cept for rain­forests. Com­mon ravens in North Amer­ica tend to be found in wild areas, whereas their cousins, com­mon crows tend to be found in areas more af­fected by human habi­ta­tion. In some parts of their range they have be­come quite ha­bit­u­ated to hu­mans and can be found in urban areas. (Boar­man and Hein­rich, 1999)

Com­mon ravens gen­er­ally roost on cliff ledges or in large trees but have also es­tab­lished nests on power-lines, in urban areas, and on bill­boards, to name only a few. (Boar­man and Hein­rich, 1999)

Phys­i­cal De­scrip­tion

Com­mon ravens are large, black birds with a wedge-shaped tail. They have a well-de­vel­oped ruff of feath­ers on the throat, which are called 'hack­les' and are used often so­cial com­mu­ni­ca­tion. These are the largest passer­ines. Adults reach up to 69 cm in length and from 689 to 1625 grams in weight. They are gen­er­ally dis­tin­guished from other Corvus species by their large size, more wedge-shaped tail, ro­bust bill, a ten­dency to soar and glide, and their fre­quent, harsh, croak­ing calls. The sexes are gen­er­ally alike, al­though fe­males may be smaller. (Boar­man and Hein­rich, 1999)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    689 to 1625 g
    24.28 to 57.27 oz
  • Range length
    69 (high) cm
    27.17 (high) in
  • Average basal metabolic rate
    5.5656 W
    AnAge

Re­pro­duc­tion

There is lit­tle in­for­ma­tion on when or how pair for­ma­tion oc­curs. Dis­plays occur be­tween in­di­vid­u­als through­out the year, some of which may be courtship. These dis­plays are most in­tense in the fall and win­ter. There is ev­i­dence that pairs stay to­gether through­out the year but no con­crete ev­i­dence that mat­ing oc­currs for life. Fe­males in­vite cop­u­la­tion by crouch­ing slightly or open­ing, ex­tend­ing, or droop­ing their wings and shak­ing or quiv­er­ing a slightly raised tail. (Boar­man and Hein­rich, 1999)

Breed­ing and egg lay­ing oc­curs be­tween mid-Feb­ru­ary and late May, though most clutches are started in March or April. Breed­ing sea­son varies by re­gion and by the length of the win­ter. Usu­ally 3 to 7 eggs are laid per nest and in­cu­bated for 20 to 25 days. Nests are made mostly of sticks, are asym­met­ri­cal, and mea­sure 40 to 153 cm di­am­e­ter by 20 to 61 cm high at the base and 22 to 40 cm di­am­e­ter by 13 to 15 cm deep in the cup. Young leave the nest be­tween 5 and 7 weeks of age. They may then leave the area, and their fam­ily, within a week or may re­main with the par­ents for a more ex­tended pe­riod of time. Sex­ual ma­tu­rity is reached at about 3 years of age.

  • Breeding interval
    Common ravens breed once yearly.
  • Breeding season
    Breeding occurs in lmid-February through May.
  • Range eggs per season
    3 to 7
  • Average eggs per season
    5
    AnAge
  • Range time to hatching
    20 to 25 days
  • Range time to independence
    5 to 7 weeks
  • Average age at sexual or reproductive maturity (female)
    3 years
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    1095 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    3 years
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    1095 days
    AnAge

Fe­males ex­clu­sively in­cu­bate the eggs but both par­ents care for the young once they have hatched.

  • Parental Investment
  • no parental involvement
  • altricial
  • pre-fertilization
    • protecting
      • female
  • pre-hatching/birth
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • pre-independence
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • post-independence association with parents
  • extended period of juvenile learning

Lifes­pan/Longevity

A wild raven was recorded liv­ing for 13 years and 4 months. Cap­tive birds may live much longer, one cap­tive in­di­vid­ual was recorded to have lived 80 years and cap­tives at the Tower of Lon­don in Eng­land live for 44 years or more. Prob­a­bly most com­mon ravens die dur­ing their first few years of life. (Boar­man and Hein­rich, 1999)

  • Range lifespan
    Status: wild
    13 (high) years
  • Range lifespan
    Status: captivity
    >44 (high) years
  • Typical lifespan
    Status: captivity
    44 (high) years
  • Average lifespan
    Status: wild
    206 months
    Bird Banding Laboratory

Be­hav­ior

Com­mon ravens are known for their in­tel­li­gence and com­plex so­cial dy­nam­ics. They seem ca­pa­ble of learn­ing in­no­v­a­tive so­lu­tions to newly en­coun­tered prob­lems. Com­mon ravens often for­age in larger groups in areas where re­sources are con­cen­trated, and non-breed­ing in­di­vid­u­als may oc­cupy com­mu­nal roosts, but most com­monly ravens occur alone or in pairs. Breed­ing pairs es­tab­lish nest­ing ter­ri­to­ries, which vary in size with the den­sity of re­sources in the area. Mi­gra­tion has not been recorded in com­mon ravens, but pop­u­la­tions at the edges of their range may make shorter sea­sonal move­ments to avoid ex­treme weather. (Boar­man and Hein­rich, 1999)

Com­mon ravens walk on the ground or fly. They may also glide and soar, which they do more often than Amer­i­can crows. (Boar­man and Hein­rich, 1999)

  • Range territory size
    5.1 to 40.5 km^2

Com­mu­ni­ca­tion and Per­cep­tion

Com­mon ravens are very vocal an­i­mals, with a di­verse suite of calls and non-vo­cal sounds for dif­fer­ent pur­poses and so­cial con­texts. From 15 to 33 cat­e­gories of vo­cal­iza­tions have been de­scribed in this species. There are alarm calls, com­fort sounds, chase calls, and calls de­signed for ad­ver­tis­ing ter­ri­to­ries. Com­mon ravens may be able to mimic sounds of other an­i­mals but this has not been un­am­bigu­ously doc­u­mented. It is also pos­si­ble that they are sim­ply ca­pa­ble of a huge di­ver­sity of sounds and in­no­va­tion enough to cre­ate calls that sound like those of oth­ers. Young birds en­gage in vocal play, in which they seem­ingly go through their en­tire reper­toire of sounds, pitches, and vol­umes for min­utes or hours at a time. Non vocal sounds in­clude wing whis­tles and bill snap­ping. (Boar­man and Hein­rich, 1999)

Com­mon ravens also com­mu­ni­cate with phys­i­cal dis­plays of ei­ther threat or ap­pease­ment to sub­or­di­nate and dom­i­nant ravens. Ter­ri­to­r­ial pairs chase in­trud­ers for sev­eral kilo­me­ters and may en­gage in aer­ial fights. Tac­tile cues via al­lo­preen­ing are also used. Com­mon ravens per­ceive their en­vi­ron­ment through vi­sion, some chem­i­cal cues, tac­tile, and au­di­tory stim­uli. (Boar­man and Hein­rich, 1999)

Food Habits

Com­mon ravens are mainly scav­engers. They eat a wide array of an­i­mal foods, in­clud­ing arthro­pods, am­phib­ians, small mam­mals, birds, rep­tiles, and car­rion. They are at­tracted to car­rion and eat also the in­sects that feed on car­rion (chiefly on mag­gots and bee­tles). They are also known to eat the af­ter­birth of ewes and other large mam­mals. Veg­etable foods in­clude grains, acorns, fruits, and buds. Stom­ach analy­ses show that the diet is made up pri­mar­ily of mam­malian flesh, fol­lowed by in­sects and birds. Com­mon ravens take their food from the ground and will store foods of all kinds, in­clud­ing nuts, bones, eggs, and meat. Young ravens begin to ex­per­i­ment with caching ed­i­ble and non-ed­i­ble ob­jects soon after leav­ing the nest. (Boar­man and Hein­rich, 1999)

  • Animal Foods
  • birds
  • mammals
  • amphibians
  • reptiles
  • eggs
  • carrion
  • insects
  • terrestrial non-insect arthropods
  • Plant Foods
  • seeds, grains, and nuts
  • fruit

Pre­da­tion

Com­mon ravens are rarely ob­served being preyed on, even as eggs or young in the nest. Preda­tors on nestlings may in­clude large hawks and ea­gles, other ravens, owls, and martens. Golden ea­gles, great horned owls, and coy­otes have been ob­served at­tack­ing nests and fledg­lings. Adults are usu­ally suc­cess­ful at de­fend­ing their young and will vig­or­ously chase preda­tors away. Adults are wary of ap­proach­ing novel kinds of car­rion and new sit­u­a­tions and will often only ap­proach after the pres­ence of blue jays and Amer­i­can crows makes it clear that no dan­ger is near. (Boar­man and Hein­rich, 1999)

Ecosys­tem Roles

Com­mon ravens con­sume car­rion, thereby help­ing in nu­tri­ent cy­cling. They are also im­por­tant preda­tors of arthro­pods, mam­mals, and birds in the ecosys­tems in which they live.

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Com­mon ravens eat car­rion, which helps by re­mov­ing dead an­i­mals that may har­bor dis­eases.

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Com­mon ravens some­times eat crops such as grains, nuts, and fruits, and have been ac­cused of killing or maim­ing small live­stock. They may also neg­a­tively af­fect con­ser­va­tion ef­forts aimed at desert tor­toises, sand­hill cranes, and Cal­i­for­nia con­dors. (Boar­man and Hein­rich, 1999)

  • Negative Impacts
  • crop pest

Con­ser­va­tion Sta­tus

Com­mon ravens have been per­se­cuted by hu­mans for al­legedly prey­ing on lambs and crops. They are often shot, poi­soned, or cap­tured in traps. Ravens have been killed on a local scale in order to pro­tect other en­dan­gered species pro­grams, such as the pro­grams to pro­tect desert tor­toises and sand­hill cranes, where ravens were im­pli­cated in pre­da­tion on those an­i­mals. In some parts of their range, com­mon ravens have been ex­tir­pated but some pop­u­la­tions are be­com­ing re-es­tab­lished. (Boar­man and Hein­rich, 1999)

Other Com­ments

Com­mon ravens are very im­por­tant in na­tive cul­tures through­out their range. Raven is a com­mon and im­por­tant mythic crea­ture in west­ern Na­tive Amer­i­can tra­di­tions. (Boar­man and Hein­rich, 1999)

Con­trib­u­tors

Tanya Dewey (au­thor, ed­i­tor), An­i­mal Di­ver­sity Web.

Rachel Berg (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

carrion

flesh of dead animals.

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

holarctic

a distribution that more or less circles the Arctic, so occurring in both the Nearctic and Palearctic biogeographic regions.

World Map

Found in northern North America and northern Europe or Asia.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

scavenger

an animal that mainly eats dead animals

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

taiga

Coniferous or boreal forest, located in a band across northern North America, Europe, and Asia. This terrestrial biome also occurs at high elevations. Long, cold winters and short, wet summers. Few species of trees are present; these are primarily conifers that grow in dense stands with little undergrowth. Some deciduous trees also may be present.

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

tundra

A terrestrial biome with low, shrubby or mat-like vegetation found at extremely high latitudes or elevations, near the limit of plant growth. Soils usually subject to permafrost. Plant diversity is typically low and the growing season is short.

visual

uses sight to communicate

Ref­er­ences

Chan­dler, Rob­bins, Bruun, Zim, Golden, A GUIDE TO BIRDS OF NORTH AMER­ICA, Golden & Press, New York, 1966. (pgs 212-213)

Good­win, CROWS OF THE WORLD, 2nd Edi­tion, British Mu­seum, 1986. (pgs. 124-130)

Ter­res, John K, THE AU­DOBON SO­CI­ETY EN­CY­CLO­PE­DIA OF NORTH AMER­I­CAN BIRDS,

Boar­man, W., B. Hein­rich. 1999. Corvus corax: Com­mon Raven. The Birds of North Amer­ica, 476: 1-32.

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