Adult female (19,116, Powder River; Captain W. F. Raynolds, U. S. A.). Scarcely different from the male. Above rather paler slaty; the darker shaft-streaks rather more distinct than in the male, although they are not conspicuous. Beneath with the rufous bars rather broader, the dark shaft-streaks less distinct; tibiæ about equally barred with pinkish-rufous and white. Wing, 7.70; tail, 6.90; tarsus, 2.10; middle toe, 1.40. Fourth and fifth quills equal and longest; third equal to sixth; second equal to seventh; first three inches shorter than longest.
Young male (41,890, Philadelphia; J. Krider.) Above umber-brown; feathers of the head above edged laterally with dull light ferruginous; those of the back, rump, the upper tail-coverts, scapulars, and wing-coverts bordered with the same; scapulars and rump showing large, partially exposed, roundish spots of pure white. Tail as in adult. Sides of the head and neck strongly streaked, a broad lighter supraoral stripe apparent. Beneath white, with a slight ochraceous tinge; cheeks, throat, and jugulum with fine narrow streaks of dusky-brown; breast, sides, and abdomen with broader longitudinal stripes of clear umber (less slaty than the back), each with a darker shaft-line; on the flanks the stripes are more oval; tibiæ more dingy, markings fainter and somewhat transverse; anal region and lower tail-coverts immaculate white.
Young female (12,023, Fort Tejon, California; J. Xantus). Similar in general appearance to the young male. Markings beneath broader, and slightly sagittate in form, becoming more transverse on the flanks; paler and more reddish than in the young male; tibiæ with brownish-rufous prevailing, this in form of broad transverse spots.
Hab. Entire continent of North America, south to Panama; Bahamas (but not West Indies, where replaced by A. fringilloides, Vig.).
Localities: Oaxaca (Scl. 1858, 295); Central America (Scl. Ibis, I, 218); Bahamas (Bryant, Pr. Bost. Soc. VII, 1859); City of Mexico (Scl. 1864, 178); Texas, San Antonio (Dresser, Ibis, 1866, 324); Western Arizona (Coues); Mosquito Coast (Scl. & Salv. 1867, 280); Costa Rica (Lawr. IX, 134).
LIST OF SPECIMENS EXAMINED.
National Museum, 51; Philadelphia Academy, 14; New York Museum, 7; Boston Society, 5; Museum, Cambridge, 9; Cab. G. N. Lawrence, 1; Coll. R. Ridgway, 4; Museum W. S. Brewer, 1. Total, 92.
| Sex. | Wing. | Tail. | Culmen. | Tarsus. | Middle Toe. | Specimens. |
|---|---|---|---|---|---|---|
| ♂ | 6.45–7.00 | 5.70–5.90 | .40–.00 | 1.85–1.95 | 1.10–1.20 | 30 |
| ♀ | 7.50–8.80 | 6.90–8.20 | .50–.60 | 2.20–2.25 | 1.45–1.55 | 40 |
Specimens from different regions vary but little in size. The largest are 4,198, ♀, San Francisco, Cal., winter, 16,957, ♀, Hudson’s Bay Territory, and 55,016, ♀, Mazatlan, Mexico, in which the wing ranges from 8.40 to 8.50, the tail 7.00. The smallest females are 45,826, Sitka, Alaska, and 11,791, Simiahmoo, W. T., in which the wing measures about 7.80. A female (32,499) from Orizaba, Mexico, one (8,513) from Fort Yuma, Cal., and one (17,210) from San Nicholas, Lower California, have the wing 8.00, which is about the average. The largest males are 54,336, Nulato, Alaska, 58,137, Kodiak, Alaska, 27,067, Yukon, mouth of Porcupine, and 55,017, Mazatlan, Mexico, in which the wing measures 7.00, the tail 5.60. The smallest males are 5,990, Orange, N. J., 8,514, Shoalwater Bay, W. T., 21,338, Siskiyou Co., Cal., 37,428, Orizaba, Mexico, and 5,584, Bridger’s Pass, Utah; in this series the wing measures 6.50–6.70, the tail 5.40–5.60. A specimen from Costa Rica measures: wing 6.70, tail 5.35. Thus the variation in size will be seen to be an individual difference, rather than characteristic of any region. Some immature specimens from the northwest coast of North America (as 45,828, ♂, Sitka, Rus. Am., 5,845, ♂, Fort Steilacoom, W. T., 11,791, Simiahmoo, Puget Sound, and 8,514, Shoalwater Bay, W. T.) are much darker than others, the brown above inclining to blackish-sepia; no other differences, however, are observable. An adult from the Yukon (54,337, ♀) has the rufous bars beneath remarkably faint, although well defined; another (19,384, ♀, Fort Resolution), in immature plumage, has the longitudinal markings beneath so faint that they are scarcely discernible, and the plumage generally has a very worn and faded appearance. A male in fine plumage (10,759, Fort Bridger, Utah) has the delicate reddish-rufous beneath so extended as to prevail, and with scarcely any variegation on the sides and tibiæ; the bars on the tail, also, are quite obsolete.
Habits. This species is one of the most common Hawks of North America, and its geographical range covers the entire continent, from Hudson’s Bay to Mexico. Sir John Richardson mentions its having been met with as far to the north as latitude 51°. Drs. Gambel and Heermann, and others, speak of it as abundant throughout California. Audubon found it very plentiful as far north as the southern shore of the Gulf of St. Lawrence. It has been obtained in New Mexico by Mr. McCall, in Mexico by Mr. Pease, in Washington Territory by Dr. Cooper and Dr. Suckley, in Alaska by Mr. Dall, at Fort Resolution by Mr. Kennicott, at Fort Simpson by Mr. B. R. Ross, etc. Messrs. Sclater and Salvin give it as a rare visitant of Guatemala. It has been ascertained to breed in Massachusetts, New Jersey, Wisconsin, California, and Pennsylvania, and it probably does so not only in the intervening States and Territories, but also in all, not excepting the most southern, Florida, where its nest was found by Mr. Wurdemann.