Parabuteo unicinctus

The Harris's hawk (Parabuteo unicinctus) formerly known as the bay-winged hawk or dusky hawk, is a medium-large bird of prey that breeds from the southwestern United States south to Chile, central Argentina, and Brazil. Birds are sometimes reported at large in Western Europe, especially Britain, but it is a popular species in falconry and these records almost certainly all refer to escapes from captivity. The name is derived from the Greek para, meaning beside, near or like, and the Latin buteo, referring to a kind of buzzard; uni meaning once; and cinctus meaning girdled, referring to the white band at the tip of the tail. John James Audubon gave this bird its English name in honor of his ornithological companion, financial supporter, and friend Edward Harris. The Harris's hawk is notable for its behavior of hunting cooperatively in packs consisting of tolerant groups, while other raptors often hunt alone. Harris hawks' social nature has been attributed to their intelligence, which makes them easy to train and have made them a popular bird for use in falconry. This medium-large hawk is roughly intermediate in size between a peregrine falcon (Falco peregrinus) and a red-tailed hawk (Buteo jamaicensis). Harris's hawks range in length from 46 to 59 cm (18 to 23 in) and generally have a wingspan of about 103 to 120 cm (41 to 47 in) These hawks have a brownish plumage, reddish shoulders and tail feathers with a white base and white tip. They exhibit sexual dimorphism with the females being larger by about 35%. In the United States, the average weight for adult males is about 701 g (1.545 lb), with a range of 546 to 850 g (1.204 to 1.874 lb), while the adult female average is 1,029 g (2.269 lb), with a range of 766 to 1,633 g (1.689 to 3.600 lb). They have dark brown plumage with chestnut shoulders, wing linings, and thighs, white on the base and tip of the tail, long, yellow legs and a yellow cere. The vocalizations of the Harris's hawk are very harsh sounds. The juvenile Harris's hawk is mostly streaked with buff, and appears much lighter than the dark adults. When in flight, the undersides of the juveniles' wings are buff-colored with brown streaking. They can look unlike adults at first glance, but the identical chestnut plumage is an aid for identification.