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



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

 brown. 



Total length, female, 22 to 24 inches; wing 17 to 17^, tail 9 inches. Male 20 to 22 inches ; wing 16 to 16^, tail 8 to 8J inches. 



Hab. — Eastern and northern North America. Spec, in Nat. Mus., Washington, and Mus. Acad., Philadelphia. 



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

 plumage very easily recognized, but very 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 lagapus, 

 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 FERKUGINEUS, Lichtenstein. 



California Squirrel Hawk* 



Butto ferrugineus, Licht. Trans. Acad. Berlin, 1838, p. 428. 

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

 Buleo Culifomicus, Hutchins' California Magazine, March, 1857. 



FiGunEs ^Gray, Genera of Birds, I, pi. 6 ; Cassin, B. of Cal. and Te.xas, I, pi. 26. 



t^dult. — Larger tiian either of tlie two preceding ; bill wide at base ; wings long ; tarsi feathered in front to the toes ; naked 

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

 and light rufous, the latter predominating on the rump 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 tlie abdomen ; flanks and axillary feathers fine bright ferruginous. 



Young. — Entire upper parts dark umber brown, sliglitly mixed witli fulvous ; upper tail coverts white, spotted with brown ; 

 nnder parts pure white, witli 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 ; tibise white ; tarsi dark brown, mi.\ed with white ; under wing coverts 

 and edges of wings white. 



Total length, female, 23 to 25 inches ; wing 17 to ]T}.U tail 9 inches. 



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



This is one of the most handsome of the American Falconidie, and, though known in Euro])e 

 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 a,nd 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 diiferent. Both are described 

 and figured by us, as above. 



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

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

 as well as from California. 



