BIRDS — BLTtONINAE — BUTEO COOPERI. 



31 



quills and the bronzed or silky olive lustre of their inferior surfaces are quite remarkable. The 

 exposed edges and ends of some of the secondaries in the present specimen hav^ a distinct purple 

 lustre. On examination and comparison with some black species from Mexico, we are not 

 without a 8u.'»picion that the adult of this bird is of that color. 



The only specimen of this species is in the collection made by T. Charlton Henry, M. D., 

 United States army, at Fort Fillmore, New Mexico, and is that which is represented in our plate. 



List of specimens. 



Sub-Genus Tachytxiorchis. 

 BUTEO COOPERI, Cassin. 



Butto Cooptri, Cassin, Proc. Acad. Philad. VIII, 253, (1856.) • 



About the size of Buleo borealis, but bolongine to the same group aa Buteo erythronotus of South America, ^genus Tachytri- 

 orchis, Kaup, as restricted by Bonaparte, Conspectus Avium, p. 17.) 



Bill strong; edges of upper mandible lobed ; wings long; quills very wide and strong, fourth (juill longest; tail moderate ; 

 legs rather long, tarsus feathered in front slightly below the joint, behind and remaining portion in front naked, with about 13 

 transverse scales in front and II to 13 behind, the latter running into a circular or hexagonal form towards the joint with the 

 tibia ; claws long, rather slender, very sharp, and strongly curved. 



Tail white at its base ; external feathers, with their outer webs cinereaus and their inner webs white, mottled with cinereous ; 

 other feathers of the tail mottled and striped longitudinally with while, bright rufous, dark brown, and cinereous, darker on the 

 outer web. The rufous color most conspicuous on the iwo mi(]dle feathers a^d on the outer webs of others. A subterminal 

 transverse band of dark brown, lipped with reddish and white. 



Head above and neck behind having the feathers white at base, tipped and with longitudinal stripes of brownish black ; oack 

 and rump brownish black tinged with cinereous ; upper tail coverts white, transversely barred with dark brown and tinged with 

 rufous ; wing coverts and quills brownish cinereous, lighter on the quills ; coverts with concealed spots of white at their bases ; 

 inner webs of quills white, mottled, and irregularly banded with light ashy ; exposed ends of quills light, nearly white. Under 

 parts white, with narrow stripes of dark brown on the throat, neck and flanks ; (breast, abdomen, and under tail coverts pure 

 white.) A large spot of brownish black on the under wing coverts next to the upper edge of the wing ; other under wing coverts 

 white, with a few spots of dark brown. Tibial plumes tinged with reddish yellow. Bill dark bluish ; tarsi and toes yellow. 



Total length, about 21 j inches ; wing, 15 inches ; tail, 9 inches. 



This is the only species yet discovered within the limits of the United States which belongs to 

 the group above indicated, the species of which, as restricted, are principally South American, 

 and are, for the most part, of light colors, as in the present bird. The present bird may be easily 

 distinguished from any other North American Buteo by its light colors. 



One specimen only is in the collection, and was obtained at Santa Clara, California, by J. G. 

 Cooper, M. D. It is not in adult plumage, but is very probably sufficiently mature to indicate 

 the adult plumage, except the colors of the tail. The latter is quite remarkable and peculiar in 

 its colors, which are disposed in irregular longitudinal stripes, as above described. 



This bird is one of the most interesting and valuable of the ornithological discoveries made by 

 the exploring and surveying expeditions. It is well represented in the plate cited above, but 

 necessaril}' the figure is much reduced, and is made from the only specimen that has ever come 

 under our notice. 



