RUSSET-BACKED THRUSH 163 



HYLOCICHLA USTULATA USTULATA (Nattall) 

 RUSSET-BACKED THRUSH 

 HABITS 



The russet-backed thrush, the western race of a widely distributed 

 species, lives hi summer in a comparatively narrow range from Juneau, 

 Alaska, to San Diego County, Calif., west of the Cascades and the 

 Sierra Nevada. Throughout most of this range it is an abundant 

 summer resident and a greatly admired songster. The 1931 Check- 

 list gives it as a transient in Lower California, but M. Abbott Frazar 

 collected for William Brewster (1902) four males in the Sierra de la 

 Laguna, on May 4, 7, and 16, and a female at Triunfo on June 13, all 

 of which they both thought were settled for the season and were 

 breeding, or about to breed. There is a wide gap between southern 

 Lower California and San Diego County, where no thrushes of this 

 species are known to breed. 



In the willow thickets in the lowlands of Los Angeles County, and 

 especially along densely shaded streams, we found the russet-backed 

 thrush to be a common breeding bud. Grinnell and Wythe (1927) 

 record it as abundant in summer in the San Francisco Bay region, 

 "nesting in lowland orchards, along willow-bordered streams, and in 

 forested canyons, wherever in the whole region such occur." In the 

 Yosemite region, Grinnell and Storer (1924) found this thrush breeding 

 only among the foothills and in the valleys, in the streamside low- 

 lands. Grinnell, Dixon, and Linsdale (1930), referring to the Lassen 

 Peak region, write: "Russet-backed thrushes that lived in the section 

 in summer were restricted closely to clumps of shrubby vegetation, 

 chiefly willow and white alder growing in moist places — either border- 

 ing streams or on wet ground, as in the lower mountain meadows." 



These haunts, west of the Sierra Nevada, are in marked contrast to 

 those of the closely related olive-backed thrushes in the fir forests 

 east of that range, and very different from the summer haunts of our 

 eastern birds in the coniferous forests of northern New England and 

 eastern Canada. 



Spring. — The russet-backed thrush seems to be a rather late migrant 

 in spring, advancing rather slowly. Grinnell and Wythe (1927) say 

 that it "arrives later than most of the summer visitants in the San 

 Francisco Bay region, about the last of April; an early date is April 

 15, at Berkeley." It seems to be much later farther north. We did 

 not record it at all during the first two weeks in May in western 

 Washington, though we made careful field notes every day; it is an 

 abundant summer residentUhere, and Mr. S. F. Rathbun's notes 



