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, 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.
Habits. This Bluebird belongs to western North America, its proper domain being between the Rocky Mountains and Pacific, from Mexico to Washington Territory. Mr. Nuttall first met with this species among the small rocky prairies of the Columbia. He speaks of its habits as exactly similar to those of the common Bluebird. The male is equally tuneful throughout the breeding-season, and his song is also very similar. Like the common species he is very devoted to his mate, alternately feeding and caressing her and entertaining her with his song. This is a little more varied, tender, and sweet than that of the Eastern species, and differs in its expressions.
Nuttall describes this as an exceedingly shy bird, so much so that he found it very difficult to obtain a sight of it. This he attributes to the great abundance of birds of prey. Afterwards, in the vicinity of the village of Santa Barbara, Mr. Nuttall again saw them in considerable numbers, when they were tame and familiar.
Dr. Cooper states that these Bluebirds seem to prefer the knot-holes of the oaks to the boxes provided for them. He does not confirm Mr. Nuttall’s description of its song, which he regards as neither so loud nor so sweet as that of the Eastern species. He describes it as a curious performance, sounding as if two birds were singing at once and in different keys.
Many of this species remain in Washington Territory during the winter, where Dr. Cooper met with them in December. They associated in flocks, frequented roadsides and fences, and fed upon insects and berries.
Dr. Gambel found this species throughout the Rocky Mountains, and always in company with the Sialia arctica, being by far the more abundant species.
Dr. Kennerly mentions finding this species very abundant during his march up the Rio Grande. Through the months of November, December, and January they were always to be seen in large flocks near small streams.
The Western Bluebird constructs a nest usually of very loose materials, consisting chiefly of fine dry grasses. These are not woven into an elaborate nest, but are simply used to line the hollows in which the eggs are deposited. Near San Francisco Mr. Hepburn found a pair making use of the nest of the Hirundo lunifrons. On another occasion the Bluebirds had not only taken possession of the nest of this swallow, but actually covered up two fresh eggs with a lining of dry grasses, and laid her own above them.
The eggs, usually four in number, are of uniform pale blue of a slightly deeper shade than that of the S. sialis. They measure .87 of an inch in length by .69 in breadth.
Dr. Cooper’s subsequent observations of this species in California enabled him to add to his account of it in his report on the birds of that State. He found it abundant in all the wooded districts, except high in the mountains, and thinks they reside through the summer even in the hot valley of the Rio Grande, where he found them preparing a nest in February. On the coast they are numerous as far north as the 49th parallel. He found a nest under the porch of a dwelling-house at Santa Barbara, showing that, like our Eastern species, they only need a little encouragement to become half domesticated. They raise two broods in a season, the first being hatched early in April.
At Santa Cruz he found them even more confiding than the Eastern species, building their nests even in the noisiest streets. One brood came every day during the grape season, at about noon, to pick up grape-skins thrown out by his door, and was delightfully tame, sitting fearlessly within a few feet of the open window.
In regard to their song Mr. Ridgway states that he did not hear, even during the pairing season, any note approaching in sweetness, or indeed similar to, the joyous spring warble which justly renders our Eastern Bluebird (S. sialis) so universal a favorite.
The two Western species of Sialia, though associating during the winter in the region along the eastern base of the Sierra Nevada, are seldom seen together during the breeding-season; the S. arctica returning to the higher portions of the thinly wooded desert mountains, while the S. mexicana remains in the lower districts, either among the cottonwoods of the river valleys or among the pines around the foot-hills of the Sierra.
Erythraca (Sialia) arctica, Swains. F. B. A. II, 1831, 209, pl. xxxix. Sialia arctica, Nuttall, Man. II, 1832, 573.—Baird, Birds N. Am. 1858, 224; Rev. 64.—Sclater, Catal. 1861, 11, No. 67.—Dresser, Ibis, 1865, 478. (Texas, winter, very abundant.)—Cooper, Birds Cal. 1, 29. Sialia macroptera, Baird, Stansbury’s Rept. 1852, 314 (larger race with longer wings).
Sp. Char. Greenish azure-blue above and below, brightest above; the belly and under tail-coverts white; the latter tinged with blue at the ends. Female showing blue only on the rump, wings, and tail; a white ring round the eye; the lores and sometimes a narrow front whitish; elsewhere replaced by brown. Length, 6.25; wing, 4.36; tail, 3.00. (1875.)
Young. Male birds are streaked with white, as in S. sialis, on the characteristic ground of the adult.
Hab. Central table-lands of North America, east to mouth of Yellowstone. One individual collected at Fort Franklin, Great Bear Lake. Not common on the Pacific slope; the only specimens received coming from Simiahmoo, Fort Crook, and San Diego. Not recorded as found in Mexico. W. Arizona, Coues.
As already stated, the blue of this species is greener, more smalt-like than in sialis. The females are distinguished from those of the other species by the greener blue, entire absence of rufous, and longer wings.
In autumn and winter the blue of the male is much soiled by amber-brown edges to the feathers, this most conspicuous on the breast, where the blue is sometimes almost concealed; the plumage of the female, too, at this season is different from that of spring, the anterior lower parts being soft isabella-color, much less grayish than in spring.
Habits. This Bluebird belongs chiefly to the Central fauna, and occupies a place in the Eastern only by its appearance on its borders. It was first procured by Sir John Richardson, at Fort Franklin, in July, 1825. It is abundant throughout the central table-lands of North America, between the Pacific and