The Cooper's Hawk is a crow-sized raptor that breeds in deciduous and mixed-deciduous forests throughout the United States, southern Canada, and northern Mexico. Across this broad distribution, which is expanding northward and southward, it is an inconspicuous species. However, since the 1970s, Cooper’s Hawks have commonly nested in suburban and urban landscapes, such that it is likely the most common backyard breeding raptor across North America. It also is a frequently observed bird of passage at autumnal migration watchsites, locations where raptors concentrate in migration. The female Cooper's Hawk is about one-third larger than the male, and indeed this species shows among the greatest reversed size dimorphism of any of the world's hawks. Vocalizations, especially by the female, may be an important element of the pair bond in this highly dimorphic species. Midway in size between the larger Northern Goshawk (Accipiter gentilis) and the smaller Sharp-shinned Hawk (A. striatus), the Cooper's Hawk, like these other accipiters, has short, powerful, rounded wings and a relatively long tail that ensures marked maneuverability in its quick pursuit of birds and mammals.
The Cooper's Hawk breeds in both extensive areas of forest and smaller woodlots, as well as in pine plantations, and suburban and urban woodlands of towns and cities of all sizes. It also nests at high densities in the small wooded tracts in grasslands of the Northern Great Plains. It captures a variety of prey, mainly medium-sized, shrub- and ground-dwelling birds and mammals such as doves, jays, robins, chipmunks, and other rodents.
Some eastern populations of the Cooper's Hawk declined significantly in the mid-1900s, owing to shooting, trapping, and pesticide contamination. Many states in the eastern United States and some Canadian provinces designated the species as Threatened or Endangered in the late 1900s, but such designations were rescinded as evidence of widespread recovery of breeding populations.
Population trends generated from migration count data are available from Hawk Mountain Sanctuary and Cape May (see Table 1 ). Rosenfield (1), Rosenfield et al. (2), and McConnell (3) provided good summaries of changes in the species' distribution and abundance (see also 4). Since the 1990s, there have been concerted efforts to document habitat use in various parts of the species' range, with some emphasis on differences in the quality of nesting habitat (indexed by density and productivity) in natural versus human-altered landscapes (e.g., suburbia, plantations). Studies of this type have occurred in Arizona (5, 6) and Wisconsin (7, 1). Detailed information on nest-site use and selection is available for New Jersey and New York (8), New Mexico (9), Arizona (10), Wisconsin (11), Pennsylvania (3), and North Dakota (12). An ongoing 40-year study in Wisconsin has described nesting chronology, productivity, annual adult survival rates, dispersal, habitats and breeding density (13, 1, 14), including long-term responses of breeding birds to recent climate change (15) and genetic and morphological variation among northern populations (2, 16).
The species was named in 1828 by Charles Bonaparte (American Ornithology) for his friend and fellow ornithologist, William C. Cooper, a New York scientist and father of James C. Cooper, who was later honored in the title of the Cooper Ornithological Society (17).