A History of North American Birds, Land Birds. Volume 3. Robert Ridgway

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СКАЧАТЬ coalesced into a broken patch on the flanks; outside of the tibiæ with transverse spots of the same. Axillars plain, clear vandyke-brown, with a few nearly obsolete rusty specks near their ends; lining of the wing clear white, the feathers with central spaces of dusky-brown, which toward the edge become aggregated into a longitudinal patch; inner webs of the primaries with broad transverse spots of white, which reach nearly to the shaft; they are about thirteen in number on the longest quill. Feet yellow; base of the bill tinged with the same. Wing-formula, 2, 3–1, 4. Wing, 12.00; tail, 7.50; tarsus, 1.90; middle toe, 1.70; outer, 1.22; inner, 1.12; posterior, .77.

      ♀ (not adult? 18,258, Fort Buchanan, New Mexico; Dr. Irwin). Above continuous umber-drab, growing gradually lighter posteriorly, the tail being pale drab; no transverse bars (except a few concealed obsolete ones on back and secondaries), but all the feathers faintly bordered with paler rusty-brown, these edgings being on upper tail-coverts almost white. Tail tipped with creamy-white, and with many transverse spots or broad bars of the same on inner webs, outer feather irregularly skirted with the same, and all decidedly paler than the ground-color along their edges. Head as in the male, but forehead white, and superciliary stripe more continuous. Breast and abdomen with longitudinal lanceolate or cuneate streaks of dark vandyke-brown; patch of same on flanks more continuous than in the male; axillars unvariegated clear dark vandyke-brown; longest primary with eleven transverse spots of white; posterior outer face of tibiæ with sagittate spots of dark brown. Wing-formula, 2, 3–1, 4. Wing, 14.25; tail, 8.00; tarsus, 2.10; middle toe, 2.00.

      Juv. (♂, 32,207, South Fork of the Platte River, July 19, 1838; C. S. McCarthy). Above darker umber than the last, each feather distinctly bordered terminally with rusty-ochraceous. Beneath with a deeper cream-colored tinge, streaks blacker; flank-patch more conspicuous and uniform; axillars unvariegated dusky. Wing-formula, 2, 3–1=4. Wing, 13.25; tail, 7.25.

      Hab. Western division of North America, eastward to Illinois; Oregon to Lower California, and Texas. Localities: Texas, San Antonio and Eagle Pass (Dresser); Arizona (Coues).

      The different stages of plumage are in this by no means so well defined as in other species, there being nearly the same general appearance in all. There is, also, very little variation in different specimens of the same age. No. 8,504, (♀, Dalles, Oregon; Dr. George Suckley) has the black markings on the sides of the breast more circular, and the vandyke-black of the axillars with a few circular white spots on the edges of the feathers. Wing, 14.50; tail, 8.40. Nos. 17,204 (♀, San José, Lower California; John Xantus, January, 1860) and 18,258 (♂ ? Fort Buchanan, N. M.) have the upper surface almost perfectly continuous grayish-drab, the first absolutely unvariegated by markings, though the feathers fade a little on edges. Beneath, the white is very pure; the streaks are numerous, sharply defined and longitudinal. Wing, 13.25; tail, 7.50 (17,204).

      The American Lanner Falcon is so very closely related to the Lanners of Europe and Asia (var. lanarius and var. jugger) that it is very difficult to indicate the differences which separate them. The two Old World forms above named are more unlike each other than they are from the two American races; the var. jugger differing from mexicanus apparently only in larger size; and the var. lanarius, more like polyagrus than it is like either jugger or mexicanus, differs from polyagrus mainly in the greater amount of white on the plumage, this imparting a lighter aspect to the pileum, and causing a greater development of the light spots on the outer webs of the primaries and rectrices.

      Falco polyagrus.

      The var. polyagrus, compared with var. lanarius, is much darker, having, at all ages, the crown uniformly brown, with darker streaks, instead of having these streaks upon a white ground. The “mustache” is more distinct in the American bird, while in the European the bands on the tail are much more distinct, and the spots forming them are on the outer webs, as well as on the inner, instead of on the latter alone; the dark bars between the light spots are in the American bird much narrower and more numerous, and in the young the light ones come to the edge of the web, instead of being enclosed within the dark color. Two very young birds (i.e. in first perfect plumage) appear almost identical until closely examined, the chief differences being a lighter tint to the crown in the European, and heavier dark stripes on the breast, besides the peculiar character of the tail-spots, which are always distinctive. In shades of color, there is not the slightest difference.

      I have seen no specimen of any of the Old World forms in the plumage corresponding to that transversely barred above, described here as the adult, though figures of the adult lanarius indicate a very similar plumage. The series of the latter race at my command is unfortunately limited to a very few immature specimens. One marked “ad.” (56,051, Hungary; Schlüter Coll.) measures as follows: Wing, 14.50; tail, 8.00; culmen, .83; tarsus, 1.90; middle toe, 1.80. Its colors are as described in the synopsis (p. 1429) for the young bird.

      The var. mexicanus and var. jugger, which are both much darker, and more uniform in the coloring of the upper parts, than var. polyagrus, are more nearly alike; in fact, the only tangible difference that I can find between a specimen of the former in the Museum of the Boston Society of Natural History (No. 1,438, ♂, Juv. Lafr. Collection; “Mexico”) and two examples of the latter in the New York Museum, consist in the larger size of the var. jugger (see synopsis), besides its whiter cheeks and more isolated and distinct “mustache.” A direct comparison of these two races may show other tangible points of distinction, or, on the contrary, may show even these slight distinguishing features to be inconstant. The former result is, however, most reasonably to be expected.

LIST OF SPECIMENS EXAMINED

      National Museum, 9; Boston Society, 2; Philadelphia Academy, 4; Museum Comp. Zoöl. 1; G. N. Lawrence, 2; R. Ridgway, 5. Total, 23.

      Habits. This is an exclusively western species, occurring from the valley of the Mississippi to the Pacific coast. Specimens have been obtained as far east as Illinois. Several others have been taken on the Upper Missouri and the Yellowstone Rivers, in Nebraska, at Fort Thorne, New Mexico, and on the Little Colorado River. A specimen was shot by Dr. Heermann on the Farallones, on the California coast; but Dr. Cooper thinks it rarely visits the coast border, though he several times saw, near San Diego, a bird which he supposed to belong to this species. At Martinez, in December, 1863, he succeeded in shooting one as it flew from its perch at the approach of the wagon in which he was riding.

      It is said to extend its migrations in summer to the Upper Columbia, avoiding the densely forest-clad regions. Dr. Heermann saw a young unfledged individual at San Francisco, from which it may be inferred that a few may breed within the State.

      The first individual of this species was taken by Dr. Townsend during his trip across the continent, in 1834. It was obtained among the mountainous regions of Oregon, near the sources of the Platte River. Mr. Cassin states that Dr. Heermann procured several specimens in the Sacramento Valley.

      Mr. Cassin remarks that this species, except in its greatly superior size and strength, bears a very close resemblance to the well-known Jugger Falcon of India, a bird much used for the purposes of falconry.

      Dr. Kennerly, who procured a single specimen of this species while his party was encamped on the Little Colorado, found it busily engaged in seeking its prey among the bushes that grew along the river-bank. It was shy, and was procured with difficulty.

      Dr. Suckley speaks of this Hawk as not at all rare in Oregon. He procured a specimen of it at Fort Dalles, in the beginning of the winter of 1854–55, which had been killed in the act of carrying off a barn-yard fowl of about its own weight, and which it had just seized near the door of a dwelling-house,—an act demonstrative of a union of courage, ferocity, and strength inferior to none of its congeners.

      Dr. Cooper characterizes this as one of the shyest of Hawks, СКАЧАТЬ