(j50 HISTORY OF THE 



other two it is so distributed that over half the surface is con- 

 cealed by it. Of the specimens in the National Museum Collec- 

 tion, some are scarcely marked at all, while in others the ground 

 color is nearly hidden. The single egg found in the second 

 nest measures .92x.69. This nest measures three inches in 

 depth by four inches in width, the central cavity being two inches 



deep." 



Turdus ustulatus swainsonii (Cab.). 



OLIVE-BACKED THRUSH, 

 PLATE XXXV. 



Migratory; common. Arrive about the first of May; begin 

 to return early in September; a few remaining late in October. 

 B. 153. R. 4a. C. 13. G. 4, 330. U. 758a. 



Habitat. Eastei-n North America; north into the Arctic re- 

 gions; west to and including the Rocky Mountains, and from 

 the upper Columbia River northwest throughout the wooded 

 lands of Alaska; breeding chiefly north of the United States; 

 wintering from the Gulf States southward into northern South 



America. 



Sp. Chak. Adult: Above, uniform olive browu, more grayish in some ex- 

 amples; a very distinct orbital ring of buff; supraloral stripe, malar region, 

 chin, throat and jugulum light buft', usually deepest toward sides of head and 

 neck; jugulum thicicly marked with very broad triangular spots of dusky browu 

 (much darker than the color of the crown), these markings more cuneate ante- 

 riorly, and continued along sides of throat in a series of longitudinal dashes, 

 usually blended into a more or less continuous submalar stripe, narrower and 

 unbroken anteriorly; chin and upper parts of throat iiinnaculate; sides of breast, 

 sides and flanks olivaceous gray; rest of lower parts pure white; breast marked 

 with distinct transverse spots of deep brownish gray; tibia light brownish gray. 

 Axillars and lining of wing deep grayish fulvous, mixed with ochraceous. {Eidg- 

 way.) <:, ,, f 



Stretch of 

 Le7igth. iviiig. iVing. Tail. Tarsus. Bill. 



Male 7.40 12.15 4.00 3.00 1.12 .53 



Female... 7.15 11.65 3.80 2.80 1.10 .50 



Iris brown; bill dusky, with under pale straw color at base; 

 legs pale brown; feet and claws a shade darker. 



This species is more a bird of the woods than the Gray- 

 cheeked Thrush,* which it so closely resembles in build, color, 



*From the observations and collections made on the upper Yukon, the Olive-backed 

 Thrush appears to be a common summer resident there, and thus ex ends its breeding range 

 within the Arctic circle. It appears to be influenced to a great extent in its ange by the pres- 

 ence or absence of woods, and its northern limit may be marked as coinciding with the tree 

 limit. Alicia;, on the contrary, extends beyond this, wherever a bunch of dwarf willows will 

 give it shelter, to the very shores of the Arctic and BehringSeas. {Nelson. ) 



