Swainson

Swainson’s Hawk

Buteo swainsoni
(Accipitridae)

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19 inches long with a 51 inch wingspan. The Swainson’s Hawk is a big bodied hawk. The wings and tail are broad but the wings are relatively long and taper noticeably at the tip. There are three color phases (morphs). The most common in our area is the light phase. The adult has a gray-brown head and a white chin patch with a reddish breast and white belly. The back and upperwing are brown. The tail is dark above and pale below with narrow dark bars. The flight feathers are dark with faint barring and contrast with the white underwing. Most of the other big bodied hawks in our area have the reverse underwing pattern with a dark under wing and light flight feathers as opposed to the pattern on the Swainson’s. The dark phase has a dark brown head, back and upperwing. The underwing is rufous. The breast is deep reddish brown with brownish barring. The intermediate phase is between the dark and light phase with a white chin and the belly is redder.

 

The Swainson’s Hawk is somewhat common in our area during migration in mid-April to mid-May and again in mid-September to mid-October. However, it is a bird of open areas and may be seen flying over the Forest but seldom actually in the Forest itself.

The Swainson’s Hawk makes a long, 10,000 km migration each year, all the way to South America. It is a highly gregarious species that forages and migrates in flocks, sometimes numbering in the thousands. During the breeding-season the diet of the Swainson’s Hawk is rodents, rabbits, and reptiles. When not breeding, however, this hawk is atypical because it almost exclusively eats insects. In many parts of its range, this hawk can be seen in agricultural landscapes. Since its diet consists of insects studies have shown that thousands of these hawks have died in Argentina as a result of the use of pesticides.

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