No. 2. 
REPORT ON BIRDS COLLECTED ON THE SURVEY 
BY S. F. BAIRD. 
BUTEO SWAINSONI, Bonaparte, (p. 19.) 1 —Swainson’sBuzzard. 
Plates XII and XIII. 
Buteo swainsoni, Bonap. Comp. List, p. 3, (1838.) 
Buteo vulgaris, Rich. & Svv. Faun. Bor. Am. Birds, p. 47. 
There are few results of any of the expeditions more interesting than the discovery by Captain 
Beckwith’s party that this hawk was abundant in the Rocky mountains. The species first 
figured and described by Richardson and Swainson as the common buzzard of Europe had been 
variously identified by American authors, but most agreed in supposing it to be the young bird 
of the western red-tailed hawk, now known as Buteo montanus. That such is not the fact, 
however, is clearly shown by Captain Beckwith’s collection, in which are three good specimens, 
all differing from each other, and one of them exactly in the plumage figured in the Fauna 
Boreali-Americana, as quoted above. 
8540. Cochetope Pass. Iris grayish brown (24.)—8539 do. same locality. Iris whitish 
25.—8541. San Luis valley, 13. Iris whitish. 
BUTEO CALURUS, Cassin, (p. 22.)—Red-tailed Black Hawk. 
Plate XIV. 
Buteo calurus, Cassin, Proc. Acad. Pliilad. VII, 1855, 281. 
Similar in general form to Buteo vulgaris and Buteo augur. Bill rather strong; edges of the upper mandible with distinct 
rounded lobes ; wings long, fourth and fifth quills longest; tail moderate, or rather short; tarsi feathered in front for nearly 
half their length; naked behind, naked portion in front having about ten transverse scales; claws large, strong, fully curved. 
Tail bright rufous above, white at base, with about eight to ten irregular and imperfect narrow bands and one wide sub¬ 
terminal band of brownish black, and narrowly tipped with reddish white; beneath silky reddish white. 
Entire plumage above and below brownish black, deeper and clearer on the back and abdomen, and paler on the throat and 
breast. Plumage of the upper parts with concealed transverse bands of white at the base of the feathers ; and of the under 
parts with circular spots and transverse bands of the same also at the base of the feathers; quills brownish black, with a large 
portion of their inner webs white, banded and mottled with pale ashy brown; under tail coverts transversely barred with brownish 
black and pale rufous. 
Total length, female about 21 inches; wing 16J, tail 9 inches. Male rather smaller. 
Not rare in the Rocky mountains. 
BUTEO OXYPTERUS, Cassin, (p. 30.) 
Plate XV. 
This species is about the size of Buteo pennsylvanicus, hut the wings and legs are much longer. 
The inner webs of the quills are dark cinereous, their inferior surfaces of a bronzed or silky 
i The number in parentheses after the scientific name refers to the page of the General Report on Birds, Pacific Railroad 
Survey, vol. ix, where the species is described in detail 
