The North American species of Turdinæ, while retained under the single genus Turdus, yet constitute several distinct groups, which we may call subgenera.
Genus TURDUS, Linnæus.
Turdus, Linnæus, Syst. Nat., ed. 10, 1758, 168. (Type, Turdus viscivorus of Europe.)—Baird, Rev. Am. Birds.
Gen. Char. Bill conical, subulate, shorter than the head; the tip gently decurved and notched (except in Hesperocichla); the rictus with moderate bristles; the wings rather
long and pointed, with small first primary (less than one fourth the second); wings considerably longer than the tail, which is firm, nearly even, with broad feathers. Tarsi variable, seldom as long as the skull, the scutellæ fused into a continuous plate, only in rare individual instances showing indications of the lines of separation.
The genus Turdus is very cosmopolitan, occurring nearly throughout the globe, excepting in Australia, and embraces species of highest perfection as singers. In the large number of species known there are many variations in external form, but the transition from one to the other is so gradual as to render it very difficult to separate them into different genera. The sections of the group we adopt are the following:—
Sexes similar.
Hylocichla. Smallest species. Bill short, broad at base; much depressed. Tarsi long and slender, longer than middle toe and claw, by the additional length of the claw; outstretched legs reaching nearly to tip of tail. Body slender. Color: above olivaceous or reddish, beneath whitish; breast spotted; throat without spots.
Turdus. Bill stouter and higher. Tarsi stout and short, scarcely longer than middle toe and claw. Body stout, generally whitish beneath and spotted. (Second quill longer than fifth?)
Planesticus. Similar to preceding. (Second quill shorter than fifth?) Beneath mostly uni-colored; unstreaked except the throat, which is whitish with dark streaks.