BIHDS — BUTEONINAE — BUTEO MONTANUS. 



27 



In this plumage, which is evidently that of the young bird, the dark spots of the under parts are usually much larger and 

 more numerous than in the young of Buteo borealis, in which we have never seen the tibiae and under tail coverts so strongly 

 barred as in the present bird. 



Dimensions. — Adult female, total length 23 to 25 inches, wing 16| to 17, tail 9 to 10 inches. Male, total length 19 to 22 

 inches, wing 15 to 16, tail 8)^ to 9 inches. 



This is a species much resembling and nearly related to the red-tailed buzzard (Buteo borealis) 

 of the States on the Atlantic, and in the examination of collections like the present made during 

 journeys across the continent, it is not without difficulty that a distinct range of locality can be 

 assigned to the two species. The most strongly characterized specimens of the bird now before 

 us are from the countries west of the Rocky mountains, but it is evident from specimens in this 

 collection that this species is not restricted to those regions. It not only inhabits the moun- 

 tains, but extends into the countries at their eastern base. 



Of this rather difficult and obscure species, we have in tbe present collection no less than 

 thirty speciifiens, which, with several others from tbe collection of the Philadelphia Academy, 

 make a series probably representing all the stages of plumage dependent on age, sex, or season. 

 This series admits of division into the three stages above described. 



Our comparisons are made with a series of twenty-eight specimens of Buteo borealis from 

 various parts of the United States east of the Rocky mountains ; generally, however, from the 

 vicinity of Philadelphia. The present species appears to be the larger, averaging in total length 

 about 24 inches in adult females, which, so far as can be determined from prepared sjJecimens, 

 is nearly two inches greater than the average of the same sex of Buteo borealis. The wing is 

 about 1^ inches longer. There are in the entire series of both species now before us not more 

 than three specimens that we have any difficulty in assigning to one species or the other, 

 though specimens of both constantly occur which cannot be recognized without difficulty, unless 

 series are at hand for comparison. 



List of specimens. 



