524 NEW YORK STATE MUSEUM 



more finely than those of the OHve-backed thrush. The ground color 

 is also greener. 



During migration this thrush is not rare in the coastal district, 

 especially around the shores of Long Island, appearing in the spring between 

 the 20th and the 30th of May. In the fall it is first observed between the 

 1 8th and 23d of September and the latest records occur between the 12th 

 and the 23d of October. It is probable that it occurs occasionally in 

 central or western New York during migration. Doctor Merriam took 

 one specimen at Locust Grove, but of all the specimens from western New 

 York which I have examined I have found none which were smaller than 

 the smallest dimensions given for the Gray-cheeked thrush and I am inclined 

 to think they were all of that species. 



Hylocichla ustulata swainsoni (Tschudi) 

 Olive-backed Thrush 



Plate 10s 



Turdus swainsoni Tschudi. Fauna Peruana. 1845-46. Orn. 28 



Merula olivacea DeKay. Zool. N. Y. 1844. pt 2, p. 73 



Hylocichla ustulata swainsoni A. O. U. Check List. Ed. 3. 1910. 



p. 361. No. 758a 



ustulata, Lat., scorched, ashy, referring to the color; swainsoni, to William Swainson, 

 English naturalist 



Description. Upper parts olive brown; under parts white, washed with 

 grayish olive on the sides and spotted on the breast and sides with dusky; 

 the chest perceptibly tinged with buff, and the eye ring, ear coverts and cheeks 

 plainly buffy. 



Length 7-7.5 inches; extent 12- 12. 5; wing 3.8-4.2; tail 2.9-3.2; bill .5; 

 tarsus I.I. 



Distribution. The Olive-backed thrush breeds in the Canadian and 

 lower Hudsonian zone from northwestern Alaska, central Keewatin, southern 

 Ungava and Newfoundland, southward to eastern Oregon, Nevada, 

 Colorado, Utah, northern Michigan, New York and the mountains of 

 Massachusetts and Pennsylvania and West Virginia; winters from southern 

 Mexico southward to Argentina. In New York it is a common summer 

 resident of the Canadian zone, both in the Catskills and in the Adirondacks, 

 being more abundant in the higher forests of the mountains than the 



