Localities: Southeastern Texas (Dresser, Ibis, 1865, 323, breeds); Arizona (Coues, Prod. 1866, 43); Costa Rica (Lawr. IX, 134).

LIST OF SPECIMENS EXAMINED.

National Museum, 12; Philadelphia Academy, 16; New York Museum, 3; Boston Society, 2; Cambridge Museum, 1; Cab. G. N. Lawrence, 7; Coll. R. Ridgway, 4; Museum, W. S. Brewer, 1. Total, 46.

Sex.Wing.Tail.Culmen.Tarsus.Middle Toe.Specimens.
9.00–9.308.00–8.50.65–.002.45–2.651.55–1.607
10.20–11.009.00–9.80.75–.802.60–2.751.65–1.8512
Var.
mexicanus, Swainson.
MEXICAN BLUE-BACKED HAWK.

Accipiter mexicanus, Swains. F. Bor.-Am. II, 1831, 45.—Jard. (ed. Wils.) Am. Orn. II, 1832, 215.—Bonap. Consp. 32 (under A. fuscus).—Cass. B. Cal. & Tex. 96.—Ib. P. A. N. S. 1855, 279; Birds N. Am. 1858, 17.—Coop. & Suckl. P. R. R. Rep’t, VII, ii, 1860, 146.—Coues, P. A. N. S. Philad. 1866, 18.—Gray, Hand List, I, 1869, 33.

Adult male (12,024, Fort Tejon, Cal.; J. Xantus). Forehead, crown, and occiput plumbeous-black, feathers of the latter with basal two-thirds snowy-white, partially exposed. Upper plumage deep plumbeous, darkest anteriorly, the back being scarcely lighter than the nape; rump fine bluish-plumbeous. No concealed white on the upper parts. Tail brownish-plumbeous, narrowly tipped with pure white, and with four sharply defined broad bands of black,—the first of which is faintest, and concealed by the coverts, the last broadest; shafts of tail-feathers deep brown throughout. Primaries and secondaries much darker than the tail, more bluish; less so, however, than the scapulars. Lores whitish, quite in contrast with the black of the forehead; cheeks and ear-coverts dark ashy, slightly washed with reddish, and with obscure darker streaks; chin and throat white, with sparse hair-like shaft-streaks of black. Breast, abdomen, sides, flanks, and tibiæ fine vinaceous-rufous; feathers (except on tibiæ) with fine hair-like shaft-streaks of black (much narrower than in cooperi); breast, abdomen, sides, and flanks with pairs of transverse ovoid white spots, not touching the shaft; on the abdomen the white and rufous bars are of about equal width; on the tibiæ the rufous is deepest, and exceeds the white; anal region barred with rufous, more faintly than the abdomen; lower tail-coverts snowy-white. Sides of the neck deep reddish-ashy, this washing the whole side of the breast. Lining of the wing reddish-white, with numerous crowded, cordate, somewhat blended spots of rufous; larger coverts transversely spotted with blackish; under side of primaries silvery-white (blackish for about the terminal inch), crossed with quadrate spots of blackish, of which there are about seven on the longest quill (fourth); the basal ones are, however, so much broken, that the number varies in different individuals.

Young male (Fort Tejon, California). Forehead, crown, occiput, and nape deep rusty-rufous; feathers with broad longitudinal streaks of pure black. Rest of upper parts deep umber, darkest on the back; feathers of back and rump, the upper tail-coverts, scapulars, and wing-coverts, broadly bordered with rusty; scapulars with concealed white spots. Tail ashy-umber, tipped (more broadly than in adult) with ashy-white, crossed by four broad bands of brownish-black; the last (or subterminal) of which is broadest, the first concealed by the coverts. Secondaries and primaries similar in color to the tail, but darker; the first showing five obsolete darker bands, and tipped (rather broadly) with pale cinnamon-rufous. Ear-coverts and cheeks fulvous-white, thickly streaked with dark brown. Lower parts white, washed with ochraceous on jugulum and breast; each feather with a central longitudinal lanceolate stripe of clear umber, the shaft of each black; these streaks are very narrow on the throat, broadest on the breast and flanks. Tibiæ with transversely ovate spots, and transverse bars of reddish-umber; lower tail-coverts with narrow shaft-streaks of darker brown. Lining of wing with cordate and ovate spots of dark brown.

Young female (42,136, Orizaba, Mexico; M. Botteri). Similar to the young male; feathers of back, etc., less broadly margined with rusty. Ochraceous wash on lower parts more decided; stripes beneath broader and less lanceolate; on the sides broadly ovate, and on the flanks in form of broad transverse bars; tibiæ more thickly spotted transversely; lower tail-coverts immaculate. Wing, 9.00; tail, 7.80; tarsus, 2.25; middle toe, 2.50. Fourth quill longest; third shorter than fifth; second intermediate between sixth and seventh; first, 2.90 shorter than longest. Graduation of tail, .90.