 |
|
|
|||
|
|||
|
|||
|
 |
|
education: birds of georgia American Crow, Corvus ossifragus
Status: Common breeding resident throughout the state. High count 1310 on Atlanta CBC 16 Dec 1979. Habitat: A variety of habitats with two basic requirements: openness for ground feeding and scattered trees for safety, loafing, nesting and roosting. Found around agricultural fields, in open landscapes with small woodlots and scattered trees, in clearings in hardwood and coniferous forest, in bottomland forests and in windbreaks on prairies. Breeding: Canada. Interior BC, Alberta, s. Saskatchewan, s. Manitoba, s.Ontario, s. Quebec, se Labrador, Newfoundland and Maritime Provinces. United States: Throughout the lower forty-eight, but absent from Olympic Mts in Washington bordering Puget Sound and dry agricultural areas east of Cascades, parts of central California, s. Utah, w. and N. AZ, MN and AK. Winter: Recorded in areas where breeding does not occur (parts of e. WA, central CA, s. UT, and n AZ. It withdraws from breeding range in OR east of Cascades and from n. CA and n NV (Verbeek and Caffrey 2002). Migration: Diurnal migrant, migrating in flocks of 20-200, occasionally 500-1000, and rarely > 2000 (Peterjohn 1989). Withdraws completely from northern portions of its breeding range, and some birds in southern portions of breeding range migrate south (Graber et al.1987). Significant migration from the north not noted in GA, but the extent and dynamics of the migration of the species in GA needs more study. Diet: Omnivorous. Wide variety of invertebrates, amphibians, reptiles, small birds and mammals, birds' eggs, nestlings and fledglings, grain crops (especially corn, soybeans and wheat), seeds and fruits, carrion and discarded human food. One study of 1340 adults showed the diet consisted of 28% animals and 72 % vegetable matter (Kalmbach 1939). Caches food on the ground, in trees and in the snow (Kilham 1989), concealing items on the ground with bits of grass or other debris. Identification: Medium- sized, all black corvid with broad wings and short tail (L 17.5 in; WS 39 in; WT 1 Lb) (Sibley 2000). Sexes alike, except that male is slightly larger than female. Adults ( > 15 mo old) have feathers glossed violet (difficult to observe), nares covered with stiff, bristle-like feathers, stout glossy black bill and brown iris. Wingtips do not reach tip of tail. In flight, wing beats "smooth and rowing" (Sibley 2000). Glides with broad wings slightly raised while ravens glide with narrow wings flat. Conservation: The American Crow has been treated as an agricultural pest for most of American history. It is still hunted across its range, and recreational hunting is the single greatest cause of mortality across the continent. In 1920's and 1930's, huge numbers were dynamited at night at roost sites. Some 26,000 crows were killed at a single roost by dynamite at Dempsey, OK on 10 Dec 1937 (Imler 1939). In GA, numbers of American Crows has decreased markedly since 1990. Examinations of crow carcasses from GA indicate that some of the mortality is due to West Nile virus, which strikes corvids with high frequency. Fortunately, crows have adapted to the cities and suburbs in GA, where food is abundant and hunting and dynamiting are forbidden. Literature cited: Imler, R.H. 1939. Comparison of the food of White-necked Raven and crows in Oklahoma. Wilson Bull. 51: 121-122.) Kalmbach, E.R. 1939. The crow in its relation to agriculture. U.S. Dep. Agric. Farmers Bull no. 1102. Kilham, L. 1989. The American Crow and the Common Raven. Texas A& M Univ. Press, College Station. Peterjohn, B.G. 1989. The Birds of Ohio. Indiana Univ. Press, Bloomington. 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.
|
||||||||
|
Visit Our Partners:
|
|
|
|
|
|
|
||
|
