22 U. S. p. R. R. EXP. AND SURVEYS — ZOOLOGY — GENERAL REPORT. 



List of specimens. 



BUTEO CALURUS, Gas sin. 



Red'tailed Black Hawk. 



Bulto calurus, Cassin, Proc. Acad. Philada. VII, p. 281, (1855.) 



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, niked 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 reddifh 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 16^, tail 9 inches. Male rather smaller. 



This remarkable buzzard bears a greater resemblance to Buteo augur, Riippell, an African 

 species, than to any other with which we are acquainted. It resembles no other American 

 species except Buteo insignatus, Cassin, but is much larger, and presents other strong points of 

 difference. To a casual observer this bird would present somewhat the appearance of the black 

 hawk of the United States, Archibuteo sanctijohannis, with the tail attached of the common 

 red-tailed buzzard, Buteo horealis, a combination hitherto quite unknown in the American 

 falconidas, but which does exist in the African Buteo augur. 



This species was described by us, as above, from a single specimen in the collection brought 

 by the party in charge of Captain John Pope, United States army, which was obtained by T. 

 Charlton Henry, M. D., United States army, in the vicinity of Fort Webster, New Mexico. 

 This able and zealous naturalist is the discover of this curious species, and has added a large 

 amount of information to the knowledge of the ornithology of western North America. To the 

 collections of this gentleman we shall liave frequent occasions to allude. 



One other specimen is in the preseut collection, and was obtained by Mr. E. Samuels at Peta- 

 luma, Sonora county, California, who found it breeding, and had the good fortune to obtain the 

 eggs. These have recently been described by Dr. Thomas M. Brewer, in his very valuable work 

 on North American Oology, now in the course of publication by the Smithsonian Institution. 



