208 U. S. p. R. E. EXP. AND SURVEYS — ZOOLOGY — GENERAL REPORT. 



T URDUS, Linnteu . 



Tardus, Linn-ehs, Systema Naturae, 1735. (Type T. viscivorus , fide G. R. Gray.) 



Bill rather stout ; commissure straight to near the tip, which is quite abruptly decurved, and usually distinctly notched; 

 culmen gently convex from base. Bill shorter than the head ; both outlines curved. Tarsi longer than the middle toe. Lateral 

 toes nearly equal ; outer longer. Wings much longer than tha tail, pointed ; the first quill spurious and very small — not one- 

 fourth the length of longest. Tail short, nearly even, or slightly emarginate. 



The essential characters of the true thrushes appear to consist in the long tarsi, without 

 distinct scutellae ; the long pointed wings, with rather short second quill and the spurious 

 primary ; and the moderately short, even tail. There are, however, several distinct groups 

 among them, of which these in the following synopsis belong to North America. 



The Turdus naevius of authors is quite different from the other species in the more slender 

 bill, longer gonys, and absence of any notch in the bill. The general appearance is, however, 

 so thrush-like that I cannot see any reason for transferring it to a separate family, as Bonaparte 

 has done. The structure of its bill assimilates it to Toxostoma ; but it differs in shorter bill, 

 even tail, booted tarsi, and long wings. The first primary is shorter also, though longer than 

 in Turdus. 



There are few species of North American birds the synonymy of which has been in such a 

 state of confusion as the small thrushes. Of these there may now be considered as well estab- 

 lished T. mustelinus, fuscescens, uslulatus, stvainsonii, aliciae, pallasii, and nanus, to which may 

 possibly have to be added T. silens of Swainson, coming between muainsonii and pallasii. In 

 regard to mustelinus there has been no difficulty, the only synonym of note being melodus of 

 Wilson. The case is, however, very different with the rest, and a brief sketch of the history 

 of each species may not be out of place. It will be well to state, as a preliminary, that Tu)dus 

 fuscescens and ustulatus have the upper parts throughout of a uniform reddish brown, without 

 any shade of olive, the throat and breast brownish yellow ; the former species with very 

 obsolete spots in these regions, lighter tlian the ground color above ; the latter with the spots 

 more distinct, and darker than the back. T. swainsonii has the back uniform olive brown, with 

 a shade of green ; the breast with distinct nearly black spots ; the sides of head and the breast yel- 

 lowish red. T. aliciae similar, but the sides of head gray, the breast white. T. 2^allasii and nanus 

 have the back brown, with a faint tinge of reddish ; but the rump, upper coverts, and tail are 

 quite foxy, considerably different from the back. The under parts are decidedly spotted. T. 

 nanus is considerably the smaller of the two ; the color beneath purer ; the sides bluish ash, rather 

 than yellowisli biown. T. silens, if really distinct from T. pallasii, is larger and more oliva- 

 ceous on the back, with the same contrast of color on the tail. The Turdus fuscescens was 

 described improperly by Wilson as T. mustelinus. Stephens, in 1817, first detected the error, 

 and called the species T. fuscescens, which name, however, remained unnoticed until brought 

 to light by Gray in the Genera of Birds. Bonaparte, in 1824, gave the name of luilsonii, by 

 which the species has generally been known. Swainson, in the Fauna Boreali Americana, 

 calls it T. mincyr after Gmelin, and applies the name ivilsonii erroneously to T. swainsonii. 

 The Turdus minor of Gmelin, in fact, applies in part to this species, but also includes characters 

 of T. swainsonii, having been compounded of the descriptions of the little thrush of Latham and 

 the little thrush of Pennant. He supposed them to be merely two different descriptions of one 

 species, whereas that of Latham belonged to fuscescens, (" above reddish brown or clay color, 

 breast yellowish, with dusky spots,") and that of Pennant to 2'. swainsonii, (" above uniform 



