OF THE HAMILTON ASSOCIATION. l6l 



this interesting buzzard assumes, according to age, sex, or the season of the 

 year. Suffice it to say, that individuals differ so much from each other as to 

 have led to the description of about a dozen different individuals as new 

 species, all of which are now attributable to Butco Swainsoni. 



In measurement this species is about the same as its nearest relative, the 

 Red-tail, averaging about 20 inches in length by about 50 in extent, but is 

 less stoutly built, has the wings longer and more pointed, and it has only 

 three of the primaries emarginate, whereas the Red-tail has four. The entire 

 upper parts are dark-brown, many of the feathers with tawny edgings, those 

 on the head showing white when disturbed. Tail feathers, ashy-gray crossed 

 with numerous dark bars, and tipped with yellowish-white. Upper tail 

 coverts, chestnut and white with blackish bars. Under-parts white, more or 

 less shaded with chestnut. A broad pectoral area of bright chestnut, usually 

 with a glacuos shade, and displaying sharp black shaft lines ; this area 

 contrasting strongly with the pure white throat. 



In younger birds the upper parts are much as already described — the 

 lower parts, including the lining of the wings, are nearly uniform fawn color, 

 thickly spotted with blackish brown. These large dark spots for the most 

 part circular or guttiform, crowd across the fore-breast, scatter on the middle 

 belly, enlarge to cross bars on the flanks, become broad arrow heads on the 

 lower belly and tibiae, and are wanting on the throat. In all stages of 

 plumage the iris of the eye is brown. 



Hab. Western North America, from Wisconsin, Illinois, Arkansas and 

 Texas to the Pacific coast ; north to the arctic regions, and south to Buenos 

 Ayres. Casual east to Massachusetts. 



Nest in a bush or tree at a height varying from 10 to 40 feet from the 

 ground. 



Dr. Coues gives an admirable history of this species in his 

 Birds of the Northwest (page 357), from which I wih here 

 make a few extracts : 



" This large hawk is very abundant in Northern Dakota 

 where it came under my almost daily observation during the 

 summer of 1873. They were to be seen an^/where in the region 

 mentioned — even far out on the prairie, miles away from the 

 timber, circlmg overhead or perched on the bare ground. In 

 alighting it generally takes advantage of some little knoll 

 commanding a view around, though it has often no more 

 prominent place than a heap of dirt from a badger's hole, from 

 which to cast about for some imprudent Gopher espied too far 

 from home, or still more ignoble game. 



