FALCONID^ — THE FALCONS. 297 



The nearest ally of this species is the B. ferox, of the Palsearctic Eealm 

 (Northen Asia and Africa and portions of Europe), which has exactly the 

 size and proportions of the present bird, and in certain stages a very 

 similar plumage. I have not seen an unquestionable adult of B. ferox, but 

 specimens almost adult, in the collection of the Boston Society of Natural 

 History, from the Himalaya Mountains, come remarkably close to B. coojjcri 

 in plumage, having like it a black spot on the under side of the wing, but 

 apparently on the under primary-coverts, instead of on the lining, near the 

 edge ; the tail is also very similarly colored. Upon the whole, I consider 

 the B. cooperi to be a good sjjecies, with B. ferox, Gmelin, of Asia, etc., as its 

 nearest relative, unless it proves to be a hybrid between Buteo horealis and 

 Archibutco fcrrugineus, which I think is less likely to be the case. 



Habits. A single individual of this bird was shot by Dr. Cooper near 

 Mountain View in Santa Clara Valley, California, in November, 1855. It still 

 remains unique in collections, and during his more recent explorations Dr. 

 Cooper has not been able to obtain any additional specimens or see any like 

 it. Those he mistook for this bird and to which he refers in his report on 

 the birds of Washington Territory, he is satisfied were only the Archihiiteo 

 ferrugineus. The suggestion of Sclater, that the bird is not distinct from 

 Buteo erythronotus, is negatived, according to INTr. Eidgway, by the fact of 

 their actually belonging to different sections of the genus. 



Genus ARCHIBUTEO, Brehm. 



Archibutco, Bkehm, 1828. (Type, Faico larjopus, Gmelin.) 

 TriorcMs, Kaup, 1829 (nee. Leach, 1816). (Same type.) 

 Butaetcs, Les.s. 1831. (Same type.) 



?Butaquila, Hodgs. 1844. (Type, Butaquila stropMata, Hodgs.) 

 ? Hemiaetus, HoDGS. \m. (Same type.) 



Char. Similar to Buteo^ but bill and feet weaker, wings longer, and tarsi feathers in 

 front, to the toes. Bill small, compressed anteriorly, but very broad through the gape; 

 upper outline of the cere ascending basally; nostril broadly oval, nearly horizontal. Tar- 

 sus densely feathered in front and on the sides down to the base of the toes ; naked be- 

 hind, where covered with irregular scales. Tarsus more than twice as long as the middle 

 toe; basal half of the toes covered with small scales; outer toe longer than the inner; 

 claws long, strongly curved, acute. Feathering of the head and neck normal. Wing 

 very long; the third to fourth quill longest; first shorter than seventh ; outer four or five 

 with inner webs deeply emarginated. Tail moderate, rounded. Plumage full and soft. 



The relationship of this well-marked genus appears to be nearest to Buteo 

 and Circus, with an approach to Circmtus in character of the plumage, espe- 

 cially the wing. The Old World species, belonging to the subgenus (?) Buta- 

 quila, numbering two or three, according to different avithors, I have not 

 seen, and consequently cannot say whether they are really congeneric with 

 the American species or not. Exclusive of these, two species are known, 



VOL. HI, 38 



