Mr. Ridgway states that he found the Rocky Mountain Bluebird nesting in Virginia City in June. Its nests were built about the old buildings, and occasionally in the unused excavations about the mines. At Austin he also found it common in July, in similar localities. On the East Humboldt Mountains it was very numerous, especially on the more elevated portions, where it nested among the rocks and, though more rarely, in the deserted excavations of woodpeckers in the stunted piñon and cedar trees. He describes it as generally very shy and difficult to obtain, seldom permitting a very near approach. In its habits it is much less arboreal than either S. mexicana or S. sialis, always preferring the open mountain portions in the higher ranges of the Great Basin.
In regard to its notes Mr. Ridgway says: “The common note of this species would, from its character, be at once recognized as that of a Bluebird. Its autumnal note, however, lacks entirely the peculiar plaintiveness so characteristic of that of our Eastern species, and is much more feeble, consisting of a simple weak chirp. Like the S. mexicana, the S. arctica was also never heard to give utterance to anything resembling the lovely spring warbling of the S. sialis.”
Family SYLVIIDÆ.—The Sylvias.
Char. Bill much shorter than head, slender, broad, and depressed at the base, distinctly notched and decurved at the tip. Culmen sharp-ridged at base. Frontal feathers reaching to the nostrils, which are oval, with membrane above, and overhung—not concealed—by a few bristles or by a feather. Rictal bristles extending beyond nostrils. Tarsi booted or scutellate. Basal joint of middle toe attached its whole length externally, half-way internally. Primaries ten; spurious primary about half the second, which is shorter than the seventh. Lateral toes equal.
The birds of this family are readily distinguished from the Paridæ by the slender bill, notched and decurved at tip; much bristled gape, sharp-ridged culmen, exposed oval nostrils, less adherent toes, etc. They are much smaller than the Turdidæ and Saxicolidæ, with much more slender, depressed bill, longer rictal bristles, etc. The short outer primary, with the primaries ten in number, distinguish them from the Sylvicolidæ.
The following synopsis will serve to characterize the American forms of their respective subfamilies. The species are all among the most diminutive in size with the exception of the Humming-Birds:—
A. Wings longer than the nearly even and emarginate tail. Scutellæ of tarsus scarcely or not at all appreciable. General color olivaceous above. No white on tail.
Nostrils naked. Scutellæ distinct on inner face of tarsus only. Head plain … Sylviinæ.
Nostrils overhung by bristly feathers. Scutellæ of tarsus not appreciable. Head with a colored central crest … Regulinæ.