174 BULLETIN 196, UNITED STATES NATIONAL MUSEUM 



toni, Paraguay, is recorded without date. A specimen of H. u. 

 ustulata was collected on January 22, 1894, at Los Gatos, Calif. 



Egg dates: Alaska: 11 records, June 1 to July 2. 



California: 124 records, April 15 to July 15; 66 records, May 19 to 

 June 9, indicating the height of the season. 



Maine: 51 records, May 29 to July 24; 26 records, June 7 to June 14. 



New Brunswick: 43 records, June 6 to June 26; 27 records, June 12 

 to June 18. 



HYLOCICHLA USTULATA SWAINSONI (Tschudi) 



OLIVE-BACKED THRUSH 



HABITS 



The wide breeding range of the two eastern forms of this species 

 includes most of the forested regions of Alaska, north and east of the 

 Pacific coastal ranges, practically all the Canadian Zone in Canada 

 and Newfoundland, and extends southward in the United States to 

 northern California, east of the Cascades and the Sierra Nevada, 

 Nevada, Utah, Colorado, northern Michigan, northern New England, 

 and in the mountains to Pennsylvania and West Virginia. 



This range includes that of the race almae, which did not appear in 

 the 1931 Check-list. Dr. H. C. Oberholser (1898), in naming and 

 describing Alma's thrush, says: "The present race differs from the 

 eastern Hylocichla ustulata swainsonii in the more grayish, less oliva- 

 ceous color of the upper surface, this being usually more noticeable on 

 the rump and upper tail-coverts. The sides and flanks also average 

 more grayish. No apparent difference in size exists. No comparison 

 with H. ustulata proper is necessary, for Hylocichla u. almae, although 

 geographically intermediate, is even less closely allied to ustulata 

 than is swainsonii." 



H. S. Swarth (1922) made some interesting observations on the 

 distribution of the thrushes of this species in the Stikine River region 

 of northern British Columbia; he writes: 



At Great Glacier, August 11, a young bird was collected, not yet able to fly, 

 that is clearly referable to swainsoni. This last record is of considerable interest 

 as it carries the breeding range of swainsoni westward in this region to a point 

 about thirty miles from the coast, the habitat of Hylocichla u. ustulata. Although 

 the habitats of the two subspecies thus approach so closely, there is no evidence 

 of intergradation of characters between them. In the Stikine River series of 

 swainsoni there is not one specimen of an equivocal character. On the contrary, 

 these birds, like those from the Yukon region, show an extreme of grayness, com- 

 pared with typical swainsoni from eastern North America, that carries them 

 farther from ustulata in appearance than are specimens from the Atlantic coast. 



In northern New England and in eastern Canada the summer 

 haunts of the olive-backed thrush are in the spruce and fir forests of 



