26 U. S. P. R. R EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 
List of specimens 
Measurements. 
Catalogue number. 
Sex and age. 
Locality. 
When collected. 
Whence and how 
obtained. 
Original number. 
Collected by — 
Point of bill to end 
of tail. 
Between tips of out- 
stretched wings. 
Wing, from carpal 
joint. 
5153 
80 miles above mouth 
of Yellowstone 
Aug. 11, 1856 
Lt. G. K. Warren 
Dr. Hayden 
22. 50 
49. 25 
14. 75 
5159 
a 
Eau qui Court, Neb.. 
Fort Randall, Neb ... 
Oct, 20, 185C 
Oct. 11, 1856 
do 
do 
23. 00 
48.00 
16. 25 
5158 
8 
do 
do 
22. 00 
49. 50 
16.00 
?? 4617 
Jamacha Ranch, Cal 
Maj. Emory 
7 
A. Schott 
??8530 
14 
do 
BUTEO MONTANUS, Nuttall. 
The Western Red-tailed Hawk. 
Buteo montanus, Nutt. Manual Orn. U. S. I, 112, (1840.) 
Falco buteo, (Linn.) Aud. Orn. Biog. IV, 508. 
Falco buteo, (Linn.) Rich, and Sw. Faun. Bor. Am. Birds. 
Buteo borealis, (Gm.) Gray, Gen. I, p. 11. 
" Buteo Swainsonii, (Bp.)" Bonap. Consp. Av. p. 19. 
Buteo Swainsonii, Bonap. Cassin B. of Cal. and Texas, 1, p. 98 
Figures.— Aud. B. of Am., pi. 372, Oct. ed., 1, pi 
Mult female. — Throat and neck before dark brown mixed with white ; the brown color more extended and with the abdomen, 
tibios and under tail coverts much more tinged with rufous than in B. borealis. Tibiae distinctly barred transversely with 
rufous. Size rather larger. General appearance similar to Buteo borealis, but rather larger, and with the wings longer; 
throat and neck before brown ; breast and abdomen white, with a very pale fulvous or rufous tinge ; sides with numerous nar- 
row lanceolate and oblong spots of dark brown and rufous ; abdomen with a broad transverse band composed of spots of the 
same description. Tibial feathers pale rufous, with numerous transverse bands of a darker shade of the same color. Under 
wing coverts pale yellowish white, with brown spots. Tail above bright rufous narrowly tipped with white, with a subterminal 
band of black, and a few indications of transverse stripes near the shafts of the feathers. Upper parts of the body dark umber 
brown, with partially concealed ashy white and pale fulvous spots and transverse bands, especially on the scapulars and shorter 
quills. Upper tail coverts reddish white, with transverse bands of dark brown. Bill dark bluish ; tarsi and toes yellow. 
This plumage can only be distinguished from B. borealis by its larger size, the greater extent of the dark color of the throat, 
and the prevalence of the rufous color of the abdomen and tibiae. In some specimens, however, the abdomen is nearly pure 
white. Another plumage of this bird, apparently adult, of both sexes is as follows, and is the most easily recognized of any 
stage : 
Adult male and female. — Like the preceding, but with the under parts pale rufous, lighter on the breast, some feathers, 
especially on the abdomen, having longitudinal lines and spots of dark brown. Tibise rufous, with transverse bars of a darker 
shade of the same color. Tail bright rufous ; tip paler, with a subterminal band of black. This second plumage, described 
above, we have never seen in Buteo borealis. 
Young. — Upper parts dark brown, edged and spotted with white tinged with rufous. Under parts white, with large ovate 
and sagittate spots of dark brown more numerous on the abdomen. Tibial plumes and under tail coverts white, with transverse 
bars and spots of dark brown. Tail above ashy brown, with transverse bands of dark brown, nearly black. Bill dark bluish 
black, or slate color ; tarsi and toes dull greenish. 
