Cotyle serripennis.
32269
Gen. Char. Bill rather small; nostrils oval, superior, margined behind, but scarcely laterally by membrane, but not at all overhung; the axes of the outline converging. Frontal feathers soft, and, like chin, without bristles. Tarsi equal to middle toe without claw; the upper end covered with feathers all round, none at lower end. Basal joint of middle toe adherent externally nearly to end; internally, scarcely half. Lateral toes about equal, their claws not reaching beyond base of middle claw. Tail slightly emarginate; the feathers broad, and obliquely rounded at end. Edge of the wing rough to the touch; the shafts of the fibrillæ of outer web of outer primary prolonged and bent at right angles into a short stiff hook. Nest (of S. serripennis) in holes in banks; eggs pure white, unspotted.
Color dull brown above.
The great peculiarity of this genus consists in the remarkable roughness of the edge of the wing, said to occur also in Psalidoprocne, Cab. The object is uncertain, but is probably to enable the bird to secure a foothold on vertical or inclined rocks, among or on which it makes its nest. A favorite breeding-place of S. serripennis is in the piers and abutments of bridges, and these hooks might render essential aid in entering into their holes.
The birds of this genus have usually been referred to Cotyle, which, however, they resemble only in color. The nostrils are exposed, instead of being overhung; the tarsus is bare below, not feathered, and the lateral claws are considerably curved, and not reaching beyond the base of the lateral, as in Cotyle. The structure of the wing is very different.
There are at least five species or races of this genus in America, although only one belongs with certainty to the United States. A second, however, (S. fulvipennis), Mexican and Guatemalan, is not unlikely to occur in Arizona or New Mexico. This differs in having the chin and throat reddish-fulvous, not mouse-gray; the belly tinged with yellow.
Stelgidopteryx serripennis, Baird.
ROUGH-WINGED SWALLOW.
Hirundo serripennis, Aud. Orn. Biog. IV, 1838, 593.—Ib. Birds Am. I, 1840, 193, pl. li. Cotyle s. Bon. Consp. 1850, 342.—Cassin.—Brewer, N. Am. Oöl. I, 1857, 106, pl. iv, fig. 50 (eggs):—Baird, Birds N. Am. 1858, 313.—Lord, Pr. R. A. Inst. IV, 1864, 116 (Br. Columbia).—Cooper & Suckley, P. R. R. Rep. XII, II, 186 (W. Terr.).—Heermann, P. R. R. X; Williamson’s Rep. 36 (San Antonio, Tex.; breeding).—Cooper, Orn. Cal. 1, 1870, 110. Stelgidopteryx s. Baird, Birds N. Am. 1858, 312; Rev. 314.
Sp. Char. (No. 32,269 ♂.) Above smoky-brown, rather deeper on the head, perhaps a little paler on the rump. Larger quills and tail-feathers dusky-brown; the secondaries and greater coverts sometimes lighter along their external edges. The under parts (for about half the total length) from bill to and including breast, with the sides of body and lining of wings, mouse-gray, rather lighter along the throat; the rest of under parts, including crissum, white, the latter with the shafts sometimes dusky, and very rarely with dusky blotches at the ends of the longer feathers.