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The crow family (Corvidae) is a large family of birds that includes jackdaws, choughs, jays, magpies and nutcrackers as well as crows and ravens. Within the Corvidae family, there are a number of different genera. Members of the genus Corvus are most commonly referred to as crows. In Canada, there are three native birds in the genus Corvus: the American crow (Corvus brachyrhynchos), the common raven (Corvus corax) and the fish crow (Corvus ossifragus). The common raven is the official bird of the Yukon.
Description
Crows and ravens are the largest members of the order Passeriformes (perching birds). They range in length from 17.5 to 70 cm. The typical crow (genus Corvus) is either wholly black (including bill and legs) or black with white, grey or brown. The crow family shows highly developed intelligence and a complex social organization.
Range and Habitat
Of the three species of Corvus native to Canada, only the fish crow (C. ossifragus) has a limited range, only reaching the southernmost portion of eastern Canada. One subspecies of the American crow, the Northwestern crow (Corvus brachyrhynchos caurinus), only inhabits the coast and islands of British Columbia, where it forages along shores, beaches, and tidal flats. Overall, however, the highly adaptable American crow (C. brachyrhynchos) occupies many habitats and feeds on both animal and vegetable matter. It breeds from north-central BC to Newfoundland, but leaves most of that range in the winter. The common raven (C. corax) is also found in most of Canada, but stays year-round.
Nesting
American crows tend to forage in open areas but prefer wooded habitats for nesting and roosting. The American crow nests mainly in deciduous and coniferous trees and, occasionally, in low bushes. The female American crow incubates clutches (groups of eggs) of 4–6 eggs.
Evolution
The family is thought to have originated during the middle of the Miocene period (23.7 to 4.9 million years ago) and undergone an initial radiation (divergence) in southeast Asia, before dispersing to Europe, the Americas and Africa. Choughs and treepies are believed to be the most ancient members of the Corvidae. From this group, magpies and, later, jays, ravens and typical crows evolved. At present, about 123 species of Corvidae are recognized.
