BIRDS-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 16j 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 Eocky 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 the present collection no less than 
thirty specimens, which, with several others from the 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 specimens, 
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. 
Catalogue number. 
Sex and age. 
Locality. 
When collected. 
Whence and how ob¬ 
tained. 
Original number. 
Collected by— 
Me 
a 
<u 
o 
2 2 
o o 
S3 
© 
Cm 
cn 
Between tips of out- g 
stretched wings. g 
2 
its. 
73 
cl 
?3 
© 
S £ 
c .5 
* -2, 
6X3 
a 
S 
5836 
Q 
Aug. 8, 1856 
527 
23.50 
53.00 
16.75 
5834 
Sept. —, 1856 
24.50 
51.00 
4581 
8531 
Q 
99 
8538 
536 
23.00 
49.00 
4372 
Q 
24.00 
54.00 
8535 
8 
March 21,1854 
22.00 
48.00 
8534 
Aug. 4, 1853 
8 
4416 
Dec. —, 1854 
4521 
Santa Clara, Cal. 
4611 
California....... 
8536 
Laguna... 
Nov. 23, 1854 
14 
8533 
Camp 149, N. M............. 
March 16, 1854 
185 
8549 
Camp 114, N. M.... „. 
Feb. 6, 1854 
71 
6957 
8 
North Platte... 
Aug. 1, 1857 
371 
W. s. Wood. 
6956 
9 
369 
4986 
22.50 
54.50 
18 00 
4985 
25.00 
53.00 
17.50 
8532 
Devil’s river, Texas. 
Nov. —, 1855 
1 
