Sitta carolinensis, var. aculeata, Cass.
SLENDER-BILLED NUTHATCH.
Sitta aculeata, Cassin, Pr. A. N. Sc. VIII, Oct. 1856, 254.—Baird, Birds N. Am. 1858, 375, pl. xxxiii, fig. 3; Review, 86.—Cooper, Orn. Cal. 1, 1870, 54. ? Sitta carolinensis, Sclater, P. Z. S. 1856, 293 (Cordova); 1858, 300 (Oaxaca); 1859, 363 (Xalapa), 373 (Oaxaca).
Sp. Char. Very similar to carolinensis; but upper secondaries with only obscure blackish blotches, instead of sharply defined longitudinal spots of clear black. Bill slenderer and more attenuated.
Hab. Western and Middle Provinces of the United States, south to Cordova, Mex. Orizaba (Alpine regions), Sumich.
The characters given above express the essential differences between this and the Eastern race of S. carolinensis. In the present form, the depth of the bill opposite its base is .14, the width .17, and .80 or more in length from the forehead; while these same measurements in var. carolinensis are .17, .22, and .70. The obsolete character of the black spots on the secondaries is a persistent feature in the var. aculeata.
Habits. This bird chiefly differs from its eastern congener in its more slender bill. There appears to be no difference in regard to their habits, at least none have been noticed, and it is probable there is none other than trivial changes caused by its opportunities of procuring food, and the kinds upon which it subsists. It is supposed to be distributed throughout Western North America, from the British Possessions to Mexico, though Dr. Cooper thinks that it is not a common bird south of San Francisco, and only to be seen there in the colder months. It has been met with at San Diego in February. He did not observe any in the Coast Mountains, near Santa Cruz, but northward they are numerous in the summer, frequenting chiefly the groves of the deciduous oaks, creeping constantly about their trunks and branches in search of insects, which they also occasionally seek on the roofs and walls of houses. Their habits are similar to those of S. canadensis, but their movements are said to be slower, and their note is a single harsh call, uttered occasionally, and responded to by their comrades. Dr. Cooper found them quite common in Washington Territory and at Puget Sound. Dr. Suckley also mentions their great abundance.
Dr. Kennerly met with this species a hundred miles west of Albuquerque, New Mexico, and quite abundant among the pines of the Sierra Madre. He speaks of its note as being peculiar.
Mr. J. K. Lord states that this species remained about Colville during the winter, when the thermometer was 30° below zero. He also mentions that he found them nesting, in June, in the branches of the tallest pine-trees, so high up as to render the obtaining their eggs almost an impossibility.
Mr. Ridgway found the Slender-billed Nuthatch abundant, throughout the