In Guatemala is found a local race differing in its lighter under colors and in the greenish tinting of its blue (S. azurea). The S. sialis is also found in the more open districts of the elevated regions where it is numerous. It is there known as “El azulejo.”
Sialia mexicana, Swains.
CALIFORNIA BLUEBIRD.
Sialia mexicana, Sw. F. B. Am. II, 1831, 202.—Sclater, P. Z. S. 1856, 293 (Cordova): 1857, 126 (California); 1859, 362 (Xalapa).—Ib. Catal. 1861, 11, No. 66.—Baird, Birds N. Am. 1858, 223; Review, 63.—Cooper & Suckley, P. R. R. XII, II, 1859, 173.—Cooper, Birds Cal. 1, 28. Sialia occidentalis, Towns., Aud.; Sialia cæruleocollis, Vigors.
Figures: Aud. B. A. II, pl. cxxxv.—Ib. Orn. Biog. V, pl. cccxciii.—Vigors, Zoöl. Beechey’s, Voy. 1839, pl. iii.
Sp. Char. Bill slender. Head and neck all round, and upper parts generally bright azure blue. Interscapular regions, sides and fore part of the breast, and sides of the belly, dark reddish-brown. Rest of under parts (with tail-coverts) pale bluish, tinged with gray about the anal region. Female duller above; the back brownish; the blue of the throat replaced by ashy-brown, with a shade of blue. Length, 6.50; wing, 4.25; tail, 2.90.
Young. Tail and wing as in adult; head, neck, back, and breast, dull brown; each feather, except on the crown, streaked centrally with white.
Hab. Western United States, from the Rocky Mountains to Pacific. Not noticed on the Missouri plains, Central British America, or at Cape St. Lucas. Found at Xalapa and Cordova, Mex., Sclater. Popocatapetl (Alpine region), Sumichrast.
As in the others, the colors of this species are much duller in fall and winter. No. 53,319, ♂ (Carson City, Nevada, Feb. 21) differs from others in the following respects: there is hardly any chestnut on the back, there being only just a tinge along each side of the interscapular region; that on the breast is interrupted in the middle, and thrown into a patch on each side of the breast, thus connecting the blue of the throat and abdomen; the blue of the throat is unusually deep.