cooperi, Cass. P. A. N. S. Philad. VIII, 1856, 253.—Ib. Birds N. Am. 1858, 31, pl. xvi.—Coop. & Suck. P. R. R. Rept. XII, ii, 1860, 148.—Gray, Hand List, I, 8.—Ridgway, P. A. N. S. Dec. 1870, 142.—Coues, Key, 1872, 43.
8525. ½
Buteo cooperi.
Sp. Char. Adult (8,525, Santa Clara, California, Oct. 1856; Dr. J. G. Cooper). Head, neck, and whole lower parts white; feathers of the head and neck with medial longitudinal streaks of black, the white prevailing on the occiput and superciliary region,—the black predominating over the cheeks, forming a “mustache”; throat with fine lanceolate blackish streaks; sides of the breast with broader, more cuneate markings of the same; flanks with narrow, lanceolate stripes, these extending sparsely across the abdomen; tibiæ, and lower tail-coverts immaculate, the inner face of the former, however, with faint specks. Upper plumage in general dark plumbeous-brown, inclining to black on the back; plumbeous clearest on primaries, which are uniformly of this color, the inner ones inclining to fine cinereous. Scapulars and wing-coverts spattered with white beneath the surface. Rump black; upper tail-coverts white tinged with rufous, and with irregular, distant transverse bars of blackish. Tail with light rufous prevailing, but this broken up by longitudinal daubs and washes of cinereous, and darker mottlings running longitudinally on both webs; basally, the ground-color approaches white; tips white, and a distinct, but very irregular, subterminal band of black, into which the longitudinal mottlings melt; outer webs of lateral feathers entirely cinereous, and without the black band. Under side of the wing white, with a large black space on the lining near the edge; under surface of primaries white anterior to their emargination, finely mottled with ashy, and with indistinct transverse bands terminally. Fourth quill longest; third shorter than fifth; second equal to sixth; first equal to tenth. Wing, 15.75; tail, 9.10; tarsus, 3.25; middle toe, 1.70.
Buteo cooperi (adult).
This remarkable Hawk is certainly not to be referred to the B. borealis, as has been suggested, the proportions of the two being quite different, while there is no similarity of plumage. In plumage, Buteo cooperi very closely resembles the adult of Archibuteo ferrugineus, and the suggestion has been made that it is a hybrid between this and the Red-tail. The markings of the head, and the general tint of the upper parts, are almost precisely as in the former bird, while the tail is exactly similar in character of markings, the only difference being the more reddish tinge and black subterminal band, which are, in fact, the only characters approximating it to the Buteo borealis. The feet are, however, very much stronger than in the A. ferrugineus, while the tarsus is very much longer than in borealis, scarcely more so, however, than in the former. The black patch on the lining of the wing, however, is a feature shared by neither of these birds, being one entirely peculiar to the Buteo cooperi. But one specimen—the one described above—is known to have been obtained. Mr. J. A. Allen, in his “Notes on some of the Rarer Birds of Massachusetts” (see “American Naturalist,” Vol. III, p. 518, and a separate paper, p. 14), mentions the capture of this species near Cambridge, Mass., but probably did not actually see it. The specimen in question being in the possession of Mr. C. J. Maynard, he kindly sent it to the Smithsonian Institution. On examination, it proved to be a young Buteo lineatus, differing from the average in somewhat lighter colors.
Hab. Santa Clara County, California.