62 CALIFORNIA ACADEMY OF SCIENCES. 



Those 1 collected in Calaveras County, at altitudes 

 varying from four tlioasand to five tliousaiid feet, were 

 in dense, damp forests, but I have also found colonies 

 ill willow thickets in grassy mountain meadows as at 

 Bear Valley near Emigrant Gap and Siena Valley, at both 

 of which places I got poor specinjens. 



According to Mr John Fannin, of Burrard's Inlet, B. C, it 

 is jin abundant summer resident of that region, arriving May 

 1, 1884, and May 12, 1885, but was not common in the latter 

 A ear until May 27. Mr. Nelson (Eeport upon the Natural 

 History Collections made in Alaska, p. 218,) says: "It breeds 

 on the Upper Yukon Biver." Prof. Bidgway says, in his 

 report on the Ornithology of the Fortieth Parallel, ]). 397, 

 that not a single individual of the smaller thrushes was 

 met with after leaving the Sierra Nevada until arriving at 

 the East Humboldt Mountains, where the olive-backed 

 thrush was encountered in considerable numbers during the 

 season of their southward migration. 



According to Baird, Brewer and Bidgway, the eggs ex- 

 hibit noticeable variations in size, shape, and shades of 

 coloring, bearing some resemblance to those of T. usfalatus. 

 Mr. Nelson says the eggs of T. n. swcdnsonii and T. alicice 

 are absolutely indistinguishable, both in shape and size, as 

 also are the nests, according to his observations — and that 

 both breed together on the Yukon Biver in Alaska, T. (dicice 

 being the more numerous on the Lower Yukon. As the 

 moutli of the Yukon Biver is nearly as far west of San Fran- 

 cisco as San Francisco is west of New York, it seems strange 

 that the individuals of T. alicice which spend the summer 

 in Alaska do not follow the Pacific Coast in their southern 

 migrations and pass through California. This remark will 

 apply to other land birds which spend the summer in Alaska 

 and other parts of the northwest coast and winter entirely 

 in the Tropics. The physical features of the coast probably 

 determine the line of flight. 



