Sp. Char. Above with the clear dark olive of swainsoni, but this even purer and more plumbeous. Upper tail-coverts (but not lower part of rump) becoming more rufous, the tail abruptly darker, richer, and more purplish-rufous, approaching to chestnut. The clear olive of the neck passes into brownish-plumbeous along sides; pectoral spots more sparse and less pure black than in T. pallasi. The white beneath is of an almost snowy purity, appreciably different from the cottony-white of T. pallasi. Wing, 3.30; tail, 3.00; bill, .36; tarsus, 1.07.
A very tangible and constant character possessed by this bird is the more slender and depressed bill, as compared with that of T. pallasi. Specimens vary only in intensity of colors; these variations very limited, and corresponding with those of T. pallasi. In all cases, however, their precise pattern and peculiar distribution is retained.
Hab. Western Province of North America, eastward from Kodiak to Cape St. Lucas. Arizona, Coues.
Habits. This small race of the Hermit Thrush was first noticed by Dr. Pickering, and described by Mr. Audubon from an imperfect skin. It has since been obtained abundantly on the Pacific slope, and Mr. Ridgway procured a specimen as far east as the East Humboldt Mountains, which he considers its eastern limit.
In its habits it is said to be, like T. pallasi, almost exclusively terrestrial. Dr. Heermann mentions finding it abundant in California, and breeding among the stunted oaks covering the sand-hills of San Francisco. Dr. Coues found it in Arizona, but speaks of it as rare and migratory, occurring chiefly in spring and autumn, and as a shy and retiring species. Dr. Cooper, in his Report on the Birds of California, describes it as shy and timid, preferring dark and shady thickets, feeding chiefly on the ground, running rapidly, and searching for insects among the leaves.
Near San Diego they began to sing about the 25th of April. The song, consisting of a few low ringing notes, resembles that of Wilson’s Thrush (T. fuscescens), and also that of T. ustulatus, but is not so loud. Their note of alarm is a loud and ringing chirp, repeated and answered by others at a long distance.
At Santa Cruz, on the first of June, Dr. Cooper met with several of their nests, which, though probably erroneously, he supposed to belong to the Dwarf Hermit Thrush. They were all built in thickets under the shade of cottonwood-trees. Each nest was about five feet from the ground, and all contained eggs, from two to four in number, in differing stages of incubation. The nests were built of dry leaves, roots, fibres, grasses, and bark,
without any mud, and were lined with decayed leaves. Their height and external diameter measured 4 inches. The diameter of the cavity was 2½ inches and the depth 2¼. The eggs measured .90 by .70 of an inch. They are of a pale bluish-green, speckled with cinnamon-brown, chiefly at the larger end.
The nest, supposed to be of this species, supplied by Dr. Cooper, is large for the bird; constructed of a base loosely made up of mosses, lichens, and coarse fibres of plants. It is a strong and compact structure of matted leaves, put together when in a moist and decaying condition; with these there are interwoven roots, twigs, and strong fibres, surrounding the nest with a stout band and strengthening the rim. In fact, it corresponds so well—as do the eggs also—with those of T. ustulatus, that it is extremely probable that they really belong to that species. The only observable difference is the absence of the Hypnum mosses characteristic of northern ustulatus.
Dall and Bannister mention in their list of Alaska birds that the species is not common there. It was also taken at Sitka and Kodiak by Bischoff.