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

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      This genus is peculiar to America, where it is distributed over the whole of the southern and the western half of the northern continent, as well as in some of the West India Islands. There appears to be but one well-characterized species,35 this one modified into representative races in the several geographical provinces over which it ranges. The species is terrestrial, inhabiting the abandoned burrows of Armadillos and Rodents. It is diurnal, possessing as much freedom of sight, hearing, and motion in the brightest sunlight, as any species of the Falconidæ.

      S. cunicularia. Colors umber-brown and ochraceous-white, the former predominating above, the latter prevailing below. Upper parts spotted with whitish; lower parts transversely barred with brown on the breast and sides, and sometimes on the abdomen. A white gular patch, and jugular collar, with a brown band between them. Legs, crissum, anal and femoral regions, always immaculate.

      Sp. Char. Adult. Above earth-brown, the whole surface covered with numerous spots of dull white,—those on the scapulars roundish, and in pairs (on both webs); of similar form, but larger and more sparse, on the wings. Anteriorly they become more longitudinal (nearly linear), and medial; on the rump and upper tail-coverts, they are nearly obsolete. Secondaries crossed by four distinct bands of dull white, the last terminal; primaries with five to six transverse series of semi-rounded spots of ochraceous-white on their outer webs; primary coverts with about three transverse series of whitish spots. Tail with five to six bands of dull white, or pale ochraceous (the last terminal), composed of transverse oval spots, those on the middle pair of feathers not touching either the shaft or the edge. Ear-coverts uniform brown, becoming gradually paler beneath the eye and on the cheeks; eyebrows, a transverse chin-patch,—covering the whole chin and jaw and reaching back beneath the auriculars, and another across the jugulum, immaculate cottony-white; shafts of the loral bristles blackish; a broad, well-defined collar across the throat, between the white malar and jugular bands, deep brown, mixed with paler spots.

      Beneath white with a faint ochraceous tinge, especially on the legs; the breast, abdomen, and sides with transverse spots of brown, this often predominating on the breast; legs, anal region, and crissum, immaculate. Whole lining of the wing immaculate creamy-white, the primary coverts, however, with large terminal spots of dusky; under surface of the primaries grayish-brown, deeper terminally, and with large, transversely ovate spots of ochraceous-white (about five in number on the longest quill), and growing larger basally.

      ♂. Wing, 6.40–7.00; tail, 3.00–3.30; culmen, .55–.60; tarsus, 1.50–1.70; middle toe, .80. (Smallest, No. 5,183, Fort Pierre, Nebraska; largest, No. 6,881, Sacramento, California.)

      ♀. Wing, 6.50–6.80; tail, 3.15–3.30; culmen, .51–.55; tarsus, 1.50–1.60; middle toe, .80. (Smallest, No. 45,020, Laredo, Texas; largest, No. 3,971, San José, Lower California.)

      Juv. Upper surface earth-brown, as in the adult, but entirely uniform, except the wings and tail; upper tail-coverts, and a large oval patch on the wing (covering the middle coverts and the posterior half of the lesser-covert region), plain isabella-white; the anterior portion of the lesser-covert region darker brown than the back. Gular region well-defined pure white; jugular collar conspicuous and unspotted. Whole lower parts immaculate isabella-white.

      Hab. Western Province of United States, from the Plains to the Pacific, and from the Rio Grande to Cape St. Lucas; Mexico.

      Localities: Xalapa (Scl. 1857, 290); Texas (Dresser, Ibis, 1865, 330; resident).

      Specimens never vary in the pattern of coloration, and but little in the relative amount of the brown and white spotting; the shade of the brown and the depth of the ochraceous tinge vary considerably, however, in different individuals,—but irrespective of locality,—the brown being paler and the white purer in summer than in fall and winter, after the new dress is freshly assumed. The brown on the breast varies considerably in quantity, being sometimes nearly uniform, thereby abruptly contrasting with the white jugular band, and again frequently with the brown hardly greater in amount than the white, the two colors being in regular bars, as on the sides and flanks.

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