Crow
The crow is a common sight across Colorado and are often seen in large flocks called murders.
About This Species
Crows are black with metallic violet gloss on the body and blue-violet and blue-green gloss on the wings. The eyes of adult birds are brown, whereas those of immature birds are blue. The call is a caw-caw or caa-caa. Crows can be confused with the common raven, which is distinguished by its larger size and wedge-shaped tail.
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Physical Characteristics
Crows are between 17 and 21 inches in length with a wingspread of 33 to 40 inches. Males range in weight from 15.5 ounces to one pound and 6.5 ounces. Females are smaller with weights of 14.75 ounces to one pound and 5.5 ounces.
Range
Common crows are widely distributed throughout North America. They breed from Newfoundland to British Columbia south to Florida, the Gulf Coast and California. Winters are spent from southern Canada southward. Crows are found throughout much of Colorado but generally reside in riparian, agricultural and urban areas. Nesting sites have been documented as high as 10,000 feet above sea level, but nests are surprisingly absent from the High Plains of Eastern Colorado and the San Luis and Gunnison valleys. Crows are year-round residents. They form large flocks during fall and winter.
Habitat
They inhabit a wide variety of areas including open coniferous, deciduous and mixed woodlands, farms, fields, river groves, shores, parks and suburban areas.
Diet
Most of their diet consists of vegetable foods including cultivated grains, seeds, wild and cultivated fruits, and nuts. However, they also eat insects, snails, millipedes, spiders, crustaceans, small reptiles, frogs, small mammals, eggs and young of birds and carrion. Around coastal areas, they behave similar to gulls by taking clams and mussels and dropping them to crack open the shells.
Reproduction
Courtship takes place on the ground or in trees. The male faces the female and fluffs his body feathers. He then partially spreads his wings and tail and proceeds to bow repeatedly while uttering a brief rattling song. Common crows demonstrate cooperative breeding. A pair may have helpers who aid in all aspects of nesting, which includes participating in the care of the offspring. Nests are built 10 to 75 feet above the ground by both the male and female and are constructed out of sticks and coarse weed stalks that are plastered together with mud or clay. It is lined with feathers, fibrous roots, beard lichen and fur of other animals. The female will lay four to seven blue-green eggs that are thickly marked and washed with different shades of brown. Both parents take turns incubating the eggs for a period of 18 days. The young are born blind and without any feathers. Their eyes open about five days after hatching, and their first flight occurs when they are about five weeks old.