American Crow (Corvus brachyrhynchos) - HBW 14, p. 626

Taxonomy: Corvus brachyrhynchos C. L. Brehm, 1822, North America = vicinity of Boston, Massachusetts, USA.
Recent molecular-genetic studies suggest that this species might be most closely related to C. corone and that the two form a sister-taxon to the Caribbean C. jamaicensis, C. nasicus and C. leucognaphalus. Genetic similarity to C. caurinus unknown, but the two may well be a single species at present owing to present species' genetic swamping of former, probably accelerated by its NW range expansion (now extending N to Hyder, in Alaska), facilitated by urbanization and agricultural development of formerly densely forested NW Pacific coast. There appears to be no distinct boundary between nominate race and hesperis, and individuals of this species found N into SE Alaska and E to C Alberta, C Saskatchewan, Nevada, Arizona and New Mexico may include hesperis. Geographical variation largely clinal: in S USA, proposed races paulus (described from Alabama) and hargravei (Great Basin) synonymized with nominate. Known to hybridize in wild with C. corax. Three subspecies recognized.