Northwestern Crow Corvus caurinus
Wily, noisy and ubiquitous, and intelligent - the crows are both loved and reviled. In the Orient, crows are linked to death and bad luck. But scientific studies have shown that crows have complex cultures and social interactions. There are stories from credible sources of crows ‘holding court’, executions and funerals for fallen comrades (Marzluff and Angell 2005). It is difficult to make sense of these observations and it indicates how little we understand of these common birds. Crows also are among the cleverest of birds perhaps approaching the intelligence of the great apes.
The northwestern crow is a seashore predator of marine invertebrates, and birds’ eggs and chicks along the Pacific Coast from Washington to southern Alaska. The crow is found mostly around human habitation but it also occurs along beaches and on seabird islands.
There have been no systematic censuses of northwestern crows but Verbeek and Butler (1999) indicated that the North American Breeding Bird Survey did not show an increase between 1980 and 1995. They thought that sudden increases in local areas are probably a result of shifts in distribution rather than population changes but further work is required.
The major food items include a variety of marine and terrestrial invertebrates. Its diet includes a beach smorgasbord of clams, whelks, crustaceans, sea urchins and small fish. On land it eats, insects, eggs and nestlings of cormorants, gulls, songbirds, oystercatchers, auklets, and herons, as well as fruits, and carrion. Some surplus food is cached for later consumption.
Butler, R. W. 1974. The feeding ecology of the northwestern crow on Mitlenatch Island, British Columbia. Canadian Field-Naturalist 88: 313-316.
Butler, R.W., N. A. M. Verbeek and H. Richardson. 1984. The breeding biology of the northwestern crow. Wilson Bulletin 96: 408-418.
Emery, N. J. and N. S. Clayton. 2004. The mentality of crows: convergent evolution of intelligence in corvids and apes. Science 306: 1903-1907.
James, P. C. and N. A. M. Verbeek. 1983. The food storage behaviour of the northwestern crow. Behaviour 85: 276-291.
Marzluff, J. M. and T. Angell. 2005. In the company of crows and ravens. Yale University Press, New Haven Connecticut.
O’Brien, E. L., A. E. Burger and R. D. Dawson. 2005. Foraging decision rules and prey species preferences of northwestern crows (Corvus caurinus). Ethology 111: 77-87.
Richardson, H. and N. A. M. Verbeek. 1986. Diet selection and optimization by northwestern crows Corvus caurinus on little neck clams Venerupis japonica. Auk 104: 263-269.
Verbeek, N. A. M. 192. Egg predation by northwestern crows: its association with human and bald eagle activity. Auk 99: 347-352.
Verbeek, N. A. M. and R. W. Butler. 1981. Cooperative breeding of the northwestern crow Corvus caurinus. Ibis 123: 183-189.
Verbeek, N. A. M. and R. W. Butler 1999. Northwestern Crow Corvus caurinus. Birds of North America, No. 407. The Birds of North America, Inc., Philadelphia, PA.