_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.
Sialia arctica, SWAINS.