The
intriguing Common Raven has accompanied people around the Northern
Hemisphere for centuries, following their wagons, sleds, sleighs,
and hunting parties in hopes of a quick meal. Ravens are among the
smartest of all birds, gaining a reputation for solving ever more
complicated problems invented by ever more creative scientists.
These big, sooty birds thrive among humans and in the back of beyond,
stretching across the sky on easy, flowing wingbeats and filling
the empty spaces with an echoing croak.
At a Glance
Habitat
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Food
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Nesting
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Behavior
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Conservation
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Mountains
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Omnivore
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Cliff
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Ground Forager
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Least Concern
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Measurements
Both Sexes
Length
2227.2
in
5669
cm
Wingspan
45.746.5
in
116118
cm
Weight
24.357.3
oz
6891625
g
Relative Size
About half again larger than an American
Crow or Chihuahuan Raven
Other Names
- Grand corbeau (French)
- Cuervo cumún, Cuervo grande (Spanish)
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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 its uncovered. Theyve
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. Theyve 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 was at least 22 years, 7
months old. It was banded and found in Nova Scotia.
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 didnt 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 |
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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 Facts
Clutch Size
37 eggs
Number of Broods
1 broods
Egg Length
1.72 in
4.45.2 cm
Egg Width
1.21.4 in
3.13.6 cm
Incubation Period
2025 days
Nestling Period
2850 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.
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Nesting
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, sheeps 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.
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 crows nest would
be.
Common Ravens are so bold, playful, and clever that theyre
almost always doing something worth watching. Theyre 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
theyre more graceful and agile than crows, which often appear
to be swimming across the sky compared to a ravens 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 whats useful and what isnt. 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
status via IUCN
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Least Concern
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Common Raven populations increased across the continent between
1966 and 2014, according to the North American Breeding Bird Survey.
Partners in Flight estimates their global breeding population to
be 20 million with 18% living in Canada, 9% in the U.S., and 3%
in Mexico. They rate a 6 out of 20 on the Continental Concern Score
and are not on the 2014 State of the Birds Watch List. 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.
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