Hawk is a common name for several species of diurnal birds of prey from widely separate families. These birds are superficially alike, being smaller than eagles and having large, keen eyes, hooked bills and sharp, curved talons. True hawks belong to the family Accipitridae, which also includes eagles and Old World vultures and contains over 288 species worldwide. Females of all species are considerably larger than males. Ten species of true hawk breed in Canada.
Buteos are the large hawks commonly seen, in spring and summer, soaring over open areas or perched on dead trees or telephone poles. The most common species across southern Canada is the red-tailed hawk (Buteo jamaicensis). All 6 Canadian species build their own nests and most nest in trees or on the sides of cliffs. Ferruginous and rough-legged hawks (B. regalisand B. lagopus, respectively) have adapted to ground nesting in open, treeless prairie or arctic tundra. Buteos feed largely on rodents and are considered beneficial to humans.
Of the accipiters (forest hawks), sharp-shinned and Cooper's hawks and northern goshawks (Accipiter striatus, A. cooperii and A. gentilis) breed across Canada in forested areas. They tend to use different prey species and may be found nesting in close proximity in mixed woodland. Sharp-shinned and Cooper's hawks feed almost exclusively on small birds. Goshawks feed heavily on hares, squirrels and grouse. Although secretive by nature, all 3 species are bold hunters and will protect their nests against all intruders.
Circus cyaneus, the northern harrier, breeds across Canada. A slow-flying, open-country hawk, it is most often observed over marshes and meadows hunting for mice and small birds.
Hawks that breed in Canada normally migrate south in winter, most moving to the southern and central US. Swainson's and broad-winged hawks (B. swainsoni, B. platypterus) winter in South America.