144 University of California Publications in Zoology [Vol. 30 



of these color variations. However, while these gray-backed birds do 

 occur throughout the east, the extreme olivaceous type of coloration 

 seen commonly in eastern birds is not found in series of breeding 

 birds from the northwest, in British Columbia and Alaska (see Bishop, 

 1900, p. 119). 



Hylocichla guttata guttata (Pallas). Alaska Hermit Thrush 



A fairly common species in the lowlands. Seen at Carcross, May 22, 

 and at Atlin upon our arrival there, May 28. The last bird was seen 

 September 19. 



Three nests were found: One, June 13, with three fresh eggs; 

 one June 23, with four fresh eggs; and one July 12, with four fresh 

 eggs. All were on the ground, the first in a clump of small willows 

 at the edge of a muskeg, the second in an opening in mixed poplar 

 and spruce woods, and the third in rather dense poplar woods. It 

 seems noteworthy that this species should be nesting upon the ground 

 here, in view of the fact that on the upper Stikine River, a short dis- 

 tance to the southward, hermit thrush nests were found placed in small 

 spruce trees several feet from the ground (Swarth, 1922, p. 303). 



Ten specimens were collected, two breeding adults, one juvenal, 

 three in the post-juvenal molt, and four immatures in fresh fall 

 plumage (nos. 44998-45001, 45003-45008). One or two of the fall 

 birds show slight intergradation toward pcdlasii, in the huffier, less 

 grayish flanks, and in dorsal coloration. 



Hylocichla guttata pallasii (Cabanis). Eastern Hermit Thrush 

 One specimen collected, an immature female on migration, August 

 23 (no. 45002). This bird is essentially like two others collected by 

 myself in the Skeena Valley (Swarth, 1924, p. 370), and, like those 

 birds, while not as bright reddish as typical pMcmi, it is distinctly 

 nearer to that form than to the darker, gray-flanked guttata, the 

 breeding bird of northern British Columbia. 



Planesticus migratorius migratorius (Linnaeus). Eastern Robin 

 Present at Carcross, May 22, and at Atlin upon our arrival there a 

 few days later. Last seen August 31. Robins breed in fair abundance 

 in the more open woods in the valleys. They shun the dense spruce 

 woods of the middle altitudes, but are present again in some numbers 

 at timber line, where the scattered balsam thickets supply needed 

 shelter. Many old nests were found in these trees. 



