TVRDUS. 575 



p. Length about 6.25-7.25, wing 3.40-3.80 (3.65), tail 2.60- 

 2.70 (2.75), culnien .50-.52 (.51), tarsus 1.10-1.25 (1.13). 

 Eggs .87 X -63. Sab. In summer, higher mountains of 

 northeastern United States (Catskills, White Moun- 

 tains, etc.), and Nova Scotia ; Illinois (autumn) ; win- 

 ter quarters unknown 757a. T. alicise bicknelli 



Eidqw. Bieknell's Thrush. 

 d*. A very distinct orbital ring of buff or whitish. (Above uniform 

 olive, varying from a grayish to a russet tint, the wings, 

 sometimes tail also, slightly browner, or less olive, than back ; 

 sides of head with a strong buffy suffusion ; chest buffy, 

 marked with triangular spots of brown or dusky. Nest in 

 bushes, usually near water, bulky, and compact, and neatly 

 constructed of mosses, shreds of bark, etc. Eggs light green- 

 ish blue, averaging decidedly paler than in T. alicice, spotted 

 with rusty brown.) 

 e 1 . Above russet-brown, the wings and tail often appreciably 

 browner or more rufescent ; chest pale buff, marked 

 with rather small and usually narrow cuneate spots 

 of dark brown ; length 6.90-7.60, wing 3.60-4.00 (3.87), 

 tail 2.80-3.30 (3.05), culmen .50-.60 (.54), tarsus 1.10- 

 1.20 (1.13). Eggs .93 X -67. Sab. Pacific coast, north 

 to Sitka ; south, in winter, through western Mexico to 

 Guatemala. 



758. T. ustulatus Nutt. Russet-backed Thrush. 

 e 2 . Above decidedly olivaceous, sometimes even inclining to 

 grayish, the wings and tail concolor with, or at least not 

 very different from, the back ; chest yellower buff, marked 

 with large, broad, dusky (sometimes blackish) triangular 

 1 spots ; length 6.35-7.55, wing 3.80-4.10 (3.96), tail 2.80- 

 3.10 (2.95), culmen .50-.55 (.52), tarsus 1.05-1.18 (1.10). 

 Eggs .90 X -65. Sab. Eastern North America, but west 

 to and including Rocky Mountains (as far as Bast Hum- 

 boldt Mountains and the upper Columbia), breeding chiefly 

 north of the United States, wintering from Gulf States 

 and Mississippi Yalley south to Cuba, Guatemala, Costa 

 Eica, Panama, and Peru.. 758a. T. ustulatus swainsonii 



(Cab.). Olive-backed Thrush. 

 c 2 . Second quill shorter than fifth, the fourth longest ; tail and its upper 

 coverts rufous, in decided contrast with the color of the back. 

 (Chest, and a distinct orbital ring, buffy, sometimes nearly white, 

 the former marked with large triangular spots of dusky. Nest on 

 ground, in damp or swampy woods, composed of dead leaves, dry 

 grasses, etc. Eggs plain greenish blue, paler than in T. muste- 

 linus and T. fuscescens.) 



