Measurements
Both Sexes
- Length
- 22–27.2 in
56–69 cm - Wingspan
- 45.7–46.5 in
116–118 cm - Weight
- 24.3–57.3 oz
689–1625 g
Relative Size
- About half again larger than an American Crow or Chihuahuan Raven
Other Names
- Grand corbeau (French)
- Cuervo cumún, Cuervo grande (Spanish)
Cool Facts
- The Common Raven is an acrobatic flier, often doing rolls and somersaults in the air. One bird was seen flying upside down for more than a half-mile. Young birds are fond of playing games with sticks, repeatedly dropping them, then diving to catch them in midair.
- Breeding pairs of Common Ravens hold territories and try to exclude all other ravens throughout the year. In winter, young ravens finding a carcass will call other ravens to the prize. They apparently do this to overwhelm the local territory owners by force of numbers to gain access to the food.
- Common Ravens are smart, which makes them dangerous predators. They sometimes work in pairs to raid seabird colonies, with one bird distracting an incubating adult and the other waiting to grab an egg or chick as soon as it’s uncovered. They’ve been seen waiting in trees as ewes give birth, then attacking the newborn lambs.
- They also use their intellect to put together cause and effect. A study in Wyoming discovered that during hunting season, the sound of a gunshot draws ravens in to investigate a presumed carcass, whereas the birds ignore sounds that are just as loud but harmless, such as an airhorn or a car door slamming.
- People the world over sense a certain kind of personality in ravens. Edgar Allan Poe clearly found them a little creepy. The captive ravens at the Tower of London are beloved and perhaps a little feared: legend has it that if they ever leave the tower, the British Empire will crumble. Native people of the Pacific Northwest regard the raven as an incurable trickster, bringing fire to people by stealing it from the sun, and stealing salmon only to drop them in rivers all over the world.
- Increasing raven populations threaten some vulnerable species including desert tortoises, Marbled Murrelets, and Least Terns. Ravens can cause trouble for people too. They’ve been implicated in causing power outages by contaminating insulators on power lines, fouling satellite dishes at the Goldstone Deep Space Site, peeling radar absorbent material off buildings at the Chinal Lake Naval Weapons center, pecking holes in airplane wings, stealing golf balls, opening campers’ tents, and raiding cars left open at parks.
- Common Ravens can mimic the calls of other bird species. When raised in captivity, they can even imitate human words; one Common Raven raised from birth was taught to mimic the word “nevermore.”
- The oldest known wild Common Raven lived to be 17 years 2 months old.
Habitat
Mountains
Common Ravens occur over most of the Northern Hemisphere in nearly any habitat (eastern forests and the open Great Plains are exceptions). These include coniferous and deciduous forests, beaches, islands, chaparral, sagebrush, mountains, desert, grasslands, agricultural fields, tundra, and ice floes. They do well around human habitations including farms, rural settlements and isolated houses. In larger towns they are often replaced by American Crows, although they do occur in some cities including Los Angeles. Human presence has allowed ravens to expand into areas where they didn’t previously occur, such as using artificial ponds and irrigation to survive in deserts and living on human garbage in some forests. Common Ravens are slowly moving back into the forests of the northeastern United States and Canada as those forests regenerate.
Food
Omnivore
Common Ravens will eat almost anything they can get hold of. They eat carrion; small animals from the size of mice and baby tortoises up to adult Rock Pigeons and nestling Great Blue Herons; eggs; grasshoppers, beetles, scorpions, and other arthropods; fish; wolf and sled-dog dung; grains, buds, and berries; pet food; and many types of human food including unattended picnic items and garbage.
Nesting
Nesting Facts
- Clutch Size
- 3–7 eggs
- Number of Broods
- 1 broods
- Egg Length
- 1.7–2 in
4.4–5.2 cm - Egg Width
- 1.2–1.4 in
3.1–3.6 cm - Incubation Period
- 20–25 days
- Nestling Period
- 28–50 days
- Egg Description
- Green, olive, or blue, often mottled with dark greenish, olive, or purplish brown.
- Condition at Hatching
- Naked except for sparse tufts of grayish down, eyes closed, clumsy, and looking like “grotesque gargoyles” according to a 1945 description.
Nest Description
Males bring some sticks to the nest, but most of the building is done by females. Ravens break off sticks around 3 feet long and up to an inch thick from live plants to make up the nest base, or scavenge sticks from old nests. These sticks, and sometimes bones or wire as well, are piled on the nest platform or wedged into a tree crotch, then woven together into a basket. The female then makes a cup from small branches and twigs. The cup bottom is sometimes lined with mud, sheep’s wool, fur, bark strips, grasses, and sometimes trash. The whole process takes around 9 days, resulting in an often uneven nest that can be 5 feet across and 2 feet high. The inner cup is 9-12 inches across and 5-6 inches deep. Nests are often reused, although not necessarily by the same birds, from year to year.
Nest Placement
Cliff
Common Ravens build their nests on cliffs, in trees, and on structures such as power-line towers, telephone poles, billboards, and bridges. Cliff nests are usually under a rock overhang. Tree nests tend to be in a crotch high in the tree, but below the canopy and typically farther down in a tree than a crow’s nest would be.
Behavior
Ground Forager
Common Ravens are so bold, playful, and clever that they’re almost always doing something worth watching. They’re less gregarious than crows, often seen alone or in pairs that stay together year round, although many may gather at a carcass or landfill. Large groups of ravens are probably young birds that have yet to pair up; ravens begin breeding at ages 2 to 4. On the ground ravens walk confidently, sometimes with a swagger, sometimes sidling. In flight they’re more graceful and agile than crows, which often appear to be swimming across the sky compared to a raven’s light wingbeats and occasional soaring. Ravens often perform aerobatics, including sudden rolls, wing-tucked dives, and playing with objects by dropping and catching them in midair. Known for their intelligence, Common Ravens can work together to solve novel problems. They sometimes follow people and possibly female cowbirds to find nests to raid. (Ravens have followed researchers as they set up artificial nests, raiding them soon after the researchers left.) Young ravens just out of the nest pick up and examine almost anything new they run across as they learn what’s useful and what isn’t. Ravens that find a big food supply (such as a large carcass or unguarded seabird nests) often cache some for later, the way other crows and jays store seeds.
Conservation
Least Concern
Common Ravens tend to do well around people, profiting from the garbage, crops, irrigation, and roadkill that accompany us. Their numbers are generally stable or rising in western North America. As eastern forests were cut down in the nineteenth and twentieth centuries ravens disappeared from most of eastern North America, but they are beginning to return to the Northeast as forest cover regenerates. In many situations ravens are unwelcome: they have been shot at, poisoned, or harassed in attempts to preserve crops (and occasionally livestock such as lambs). Ravens sometimes prey on threatened species, including Least Terns, Marbled Murrelets, and desert tortoises, and wildlife biologists have spent a lot of effort and ingenuity in trying to thwart ravens to help those species, with mixed success.
Credits
- Boarman, William I. and Bernd Heinrich. 1999. Common Raven (Corvus corax). In The Birds of North America, No. 476 (A. Poole, Ed.). The Birds of North America Online, Ithaca, New York.
- Dunne, Pete. 2006. Pete Dunne’s essential field guide companion. Houghton Mifflin, Boston.
- Ehrlich, P. R., D. S. Dobkin, and D. Wheye. 1988. The birder’s handbook. Simon & Schuster Inc., New York.
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USGS Patuxent Wildlife Research Center. 2011. Longevity Records of North American Birds.