American Crow
Corvus brachyrhynchos Order PASSERIFORMES - Family CORVIDAE
Widespread, common, and obvious, the American Crow is known by most people. What is less well known is how complex its life is. Young crows remain with their parents until they can find a home of their own, and individual relationships may last years.
Cool Facts:
American Crows congregate in large numbers in winter to sleep in communal roosts. These roosts can be of a few hundred, several thousand, or even up to two million crows. Some roosts have been forming in the same general area for well over 100 years. In the last few decades some of these roosts have moved into urban areas where the noise and mess cause conflicts with people.
Young American Crows do not breed until they are at least two years old, and most do not breed until they are four or more. In most, but not all, populations the young stay with their parents and help them raise young in subsequent years. Families may include up to 15 individuals and contain young from five different years.
The American Crow appears to be the biggest victim of West Nile virus, a disease recently introduced to North America. Crows die within one week of infection, and few seem able to survive exposure. No other North American bird is dying at the same rate from the disease, and the loss of crows in some areas has been severe.
In some areas, the American Crow has a double life. It maintains a territory year-round in which all members of its extended family live and forage together. But during much of the year, individual crows leave the home territory periodically. They join large flocks foraging at dumps and agricultural fields, and sleep in large roosts in winter. Family members go together to the flocks, but do not stay together in the crowd. A crow may spend part of the day at home with its family in town and the rest with a flock feeding on waste grain out in the country.
Despite being a common exploiter of roadkill, the American Crow is not specialized to be a scavenger, and carrion is only a very small part of its diet. Its stout bill is not strong enough to break through the skin of even a gray squirrel. It must wait for something else to open a carcass or for the carcass to decompose and become tender enough to eat.
Description:
Size: 40-53 cm (16-21 in)
Wingspan: 85-100 cm (33-39 in)
Weight: 316-620 g (11.15-21.89 ounces)
Eyes dark brown.
Legs black.
All feathers black glossed with violet.
Sex Differences:
Sexes alike in plumage, but male averages slightly larger.
Immature:
Juvenile similar to adult, but head feathers not glossy and more fluffy, inside of mouth red. Immature wing and tail feathers becoming brownish over the course of the first year.
Similar Species:
Fish Crow very similar, but smaller and with a more nasal voice.
Northwestern Crow essentially identical, but with more nasal voice.
Common Raven larger, with longer and more curved bill, shaggy throat feathers, more distinct "fingers" in the wings, a wedge-shaped tail, and a deeper and more guttural voice.
Chihuahuan Raven very similar, but with wedge-shaped tail and different voice.
Sound:
Common call a harsh "caw." Also a variety of rattles, coos, and clear notes.
Breeds from southeastern Yukon Territory eastward to Newfoundland, and southward to Florida and northern Mexico. Absent from desert regions.
Winter Range:
Winters from southern Canada southward.
Habitat:
Variety of habitats. Requires open ground for feeding and scattered trees for roosting, nesting, and refuge.
Food:
Omnivorous. Waste grain, earthworms, insects, carrion, garbage, seeds, amphibians, reptiles, mice, fruit, bird eggs and nestlings.
Behavior:
Foraging
Forages mostly on ground. Pecks from surface and digs through litter. Caches food for later use.
Reproduction:
Nest Type
Large open cup of sticks, filled with mud and grass. Lined with thick inner bowl of grapevine bark, hair, and other soft material. Usually placed high in tree.
Egg Description:
Pale bluish green with brown markings.
Clutch Size:
Usually 3-6 eggs. Range: 2-7.
Condition at Hatching
Helpless with tufts of down.
Conservation Status:
Populations slightly, but significantly increasing over last half of 20th century. Severe susceptibility to West Nile virus may cause population decreases in near future.
Other Names:
Corneille d'Amérique (French)
Cuervo americano (Spanish)
Sources used to construct this page:
McGowan, K. J. Frequently asked questions about crows.
http://birds.cornell.edu/crows/crowfaq.htm.
Verbeek, N. A. M., and C. Caffrey. 2002. American Crow (Corvus brachyrhynchos). In The Birds of North America, No. 647 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
Mike
Photo by BF member: Leslie