Roughlegs rarely nest in trees, on level ground or on man-made structures. Adult males and females exhibit different plumages, and adults and juveniles differ in appearance as well. The largest concentrations of migratory Rough-legged Hawks are observed in river valleys that run parallel to migration routes and along the shorelines of large bodies of water like the Great Lakes, where hundreds of Rough-legged Hawks are counted at spring watchsites like Whitefish Point, Michigan on Lake Superior, and at Braddock Bay and Derby Hill, New York on Lake Ontario. Many Rough-legged Hawks have breeding territories as small as one square mile. In flight the dark carpal patches of light-morph birds serve as good field marks for identifying the species. Nests, which are 60 to 90cm across and 25 to 60cm deep, are constructed of sticks and are lined with feathers, hair, moss, grass, and other greenery. Thereafter, females begin to hunt on their own. Stick nests are built on cliff ledges and in the tops of trees. In autumn, almost all Rough-legged Hawks leave the breeding grounds and migrate to wintering grounds in southern Canada and the northern United States. Rough-legged Hawk (Buteo lagopus). Dark-morph females are dark brown overall and like males, the undersides of their flight feathers are silvery. Light-morph adult males have grayish-brown backs and wings, and brown markings on their whitish underparts. Academic Press, San Diego, California. between crow and goose Measurements. Its silhouette suggests a lanky Red-tailed Hawk. Rough-legged Hawks are moderate-distance migrants that migrate across broad fronts. Hangs in wind and hovers over one spot. Rough-legged Hawks are part of the family Accipitridae, which includes 224 species of hawks, eagles, vultures, harriers, and kites. Dark-morph birds are dark throughout, except for silvery flight feathers on the undersides of their wings. The species readily undertakes long (up to 100 km) water-crossings. AND CLARK, W.S. Roughlegs call while circling and soar together or individually. 2001. Both light and dark morph Rough-legged Hawks occur in North America, but dark morphs are found nowhere else. It has a variety of color phases, from dark melanistic to light, although it never gets as light as a Krider’s red-tailed hawk. In addition, males sometimes perform “sky dance” displays. Adults have dark eyes, a wide black subterminal band on the white tail, and a black band on the trailing edge of their underwings. This fairly large raptorial species is 46–60 cm (18–24 in) with wingspan ranging from 120 to 153 cm (47 to 60 in). In North America, roughlegs typically breed in the open tundra and semi-open taiga of Alaska and Canada. It feeds on small mammals and some birds. At Hawk Mountain, approximately nine Rough-legged Hawks are counted at the Sanctuary each autumn, mainly between early November and mid-December. Although additional material may be added during incubation and brooding, the majority of nest-building occurs in the three to four weeks following a pair’s return to the breeding grounds and prior to egg-laying. A few rough-legged hawks are admitted to the clinic each winter, but it is not considered a common patient. 2002. North American birds of prey. Roughlegs will also sometimes feed on road killed animals. During the breeding season Rough-legged Hawks feed primarily on small rodents such as lemmings and voles. The Birds of North America, Inc., Philadelphia, Pennsylvania. 67-year annual average: 91992-2001: 6Record year: 31 (1961)Best chance to see: Early November.Longterm trends: Increased in 1950s and 1960s, decreasing since 1970s. Identifying Characteristics. Rough-legged Hawks have feathered legs that help conserve heat. Counted at the Sanctuary each autumn, mainly between early November and mid-December young! 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