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



former marked with white on their inner webs, the latter white at its base. Tarsi and tibite pale reddish yellow, spotted with 

 brown. 



Total length, female, 22 to 24 inches; wing 17 to 17J, tail 9 inches. Male 20 to 22 inches ; wing 16 to 16|, tiS-il 8to8J inches. 



Hai).— Eastern and northern North America. Spec, in Nat. Mus., "Washington, and Mus. Acad., Philadelphia. 



One of the most abundant of the birds of this family in the eastern States, and in adult 

 plumage very easily recognized, but yery variable in colors of plumage. The dark brown or 

 chocolate colored plumage is frequently to be met with, and in that stage this bird appears to 

 be Falco spadiceus, Gmelin. In young plumage, as described above, and especially with the 

 wide abdominal band well defined, this bird much resembles the young of Archibuteo lagopus, 

 as described immediately preceding, from which it can be distinguished by its larger size and 

 the much more numerous dark spots on the under parts in the present bird. 



AECHIBUTEO FEEEUGINEUS, Lichtenstein. 



California Squirrel Hawk. 



Buito ferrugineus, Light. Trans. Acad. Berlin, 1838, p. 428. 

 Archibuteo regalis, G. R. Gray, Gen. Birds, I, pi. 6, (plate only.) 

 Buteo Californicus, Hutchins' California Magazine, March, 1857. 



Figures — Gray, Genera of Birds, I, pi. 6 ; Cassin, B. of Cal. and Texas, I, pi. 26. 



>3duU. — Larger'than either of the two preceding ; bill wide at base ; wings long ; tarsi feathered in front to the toes ; naked 

 and scaled behind. Tibiae and tarsi bright ferruginous, with transverse nafrow stripes of black. Entire upper parts dark brown 

 and light rufous, the latter predominating on the riimp and wing coverts ; quills ashy brown, with the greater part of their 

 inner webs white ; tail above reddish white, mottled with ashy brown ; beneath pale yellowish white. Under parts of the body 

 white, with narrow longitudinal lines and lanceolate spots on the breast of reddish brown, and narrow irregular transverse lines 

 of the same color and of black on the abdomen ; flanks and axillary feathers fine bright ferruginous. 



Yovmg. — Entire upper parts dark umber brown, slightly mixed with fulvous ; upper tail coverts white, spotted with brown ; 

 under parts pure white, with a few longitudinal lines of brown on the breast, and sagittate spots of the same color on the sides 

 and abaomen, larger and more numerous on the flanks ; tibiae white ; tarsi dark brown, mixed with white ; undor wing coverts 

 and edges of wings white. 



Total length, female, 23 to 25 inches ; wing 17 to 17J^, tail 9 inches. 



Hal — Western North America. Spec, in Nat. Mus., Washington, and Mus. Acad., Philadelphia. 



This is one of the most handsome of the American Falconid^, and, though known in Europe 

 for the last twenty years, was unknown to the naturalists of this country until brought to their 

 notice by Mr. Edward M. Kern, who was attached to Colonel Fremont's expeditions. It is one 

 of the largest of its group, somewhat exceeding in size both Archibuteo sancti-johannis and lagopus. 



As usual in this family, the adult and young of the present species are quite diiferent, and 

 in well characterized specimens might readily be regarded as different. Both are described 

 and figured by us, as above. 



This bird is apparently exclusively western^ but not restricted to the countries west of the 

 Eooky mountains. In the present collection specimens are from Nebraska and New Mexico, 

 as well as from Oalifornia. 



