In its general appearance it has a marked resemblance to Wilson’s Thrush (T. fuscescens), but its habits and notes, as well as its nest and eggs, clearly point its nearer affinity to Swainson’s Thrush (T. swainsoni), its song being scarcely different from that of the latter species. Like this species, it frequents the thickets or brushwood along the mountain streams, and, except just after its arrival, it is not at all shy. In crossing the Sierra Nevada in July, 1867, Mr. Ridgway first met with this species. He describes it as an exquisite songster. At one of the camps, at an altitude of about 5,000 feet, they were found unusually plentiful. He speaks of their song as consisting of “ethereal warblings,—outbursts of wild melody.” “Although its carols were heard everywhere in the depth of the ravine, scarcely one of the little musicians could be seen.” “The song of this thrush,” he adds, “though possessing all the wild, solemn melody of that of the Wood Thrush (T. mustelinus) is weaker, but of a much finer or more silvery tone, and more methodical delivery. It is much like that of the T. swainsoni, but in the qualities mentioned is even superior.”
Dr. Cooper found its nests with eggs about the middle of June. These were most usually built on a small horizontal branch, and were very strongly constructed of twigs, grasses, roots, and leaves, usually covered on the outside entirely with the bright green Hypnum mosses peculiar to that region, which in the damp climate near the coast continue to grow in that position, and form large masses. The number of eggs is usually five.
Dr. Cooper states that these thrushes sing most in the early morning and in the evening, when numbers may be heard answering one another on all sides. They do not affect the darkest thickets so much as the Hermit Thrush, but are often seen feeding in the gardens in the open sunshine.
Dr. Suckley, who found them quite abundant in the neighborhood of Fort Steilacoom, on the edge of the forest, and in swampy land, describes the song as a low, soft, sad, and lively whistle, confined to one note, and repeated at regular intervals. Mr. Nuttall, the first to describe this form, speaks of it as shy and retiring, and as in the habit of gathering insects from the ground. His ear, so quick to appreciate the characteristics of the songs of birds, which showed a close resemblance between the notes of this bird and that of Wilson’s Thrush (T. fuscescens), enabled him to detect very distinct and easily recognizable differences. It is much more interrupted and is not so prolonged. The warble of this bird he describes as resembling wit-wit t´villia, and wit-wit, t´villia-t´villia. His call when surprised was wit-wit.
All the nests of this species that have fallen under my observation are large, compact, strongly constructed, and neat. They measure about 5 inches in their external diameter, with a depth externally of 3; the cavity
is comparatively shallow, being rarely 2 inches in depth. The external portions are constructed almost entirely of Hypnum mosses, matted together and sparingly interwoven with dry leaves and fine fibrous roots, and are lined with finer materials of the same kind. These nests most nearly resemble in their material and in their position those of Swainson’s Thrush.
Mr. Hepburn found these birds very abundant about Victoria. It does not usually breed there before the last of May, though in one exceptional instance he found a nest with young birds on the 24th of that month.
The eggs vary in size and shape, ranging from .77 to .94 in length, and from .65 to .69 in breadth. They also vary in their ground color and in the tints of the spots and markings. The ground color is light green or light blue, and the markings are variously yellowish-brown and lilac, or dark brown and slate.
Mr. Grayson found this thrush very abundant in the month of January, in the thickest of the woods, in the islands of the Three Marias, on the Pacific coast of Mexico. They were very timid and shy, more so than any bird that he saw on those islands. It frequently uttered a low plaintive whistle, and seemed solitary in its habits.
Turdus pallasi, Cabanis.