144 University of California Publications in Zoology (Vou. 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 pallasi, in the buffier, 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 pallasw, 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.