1926]  Swarth: Birds and Mammals from the Atlin Region 103

acquired barred feathers of the neck and upper breast persist until
replaced by white ones in the fall. Late in July and early in August
the rectrices and remiges are renewed, accompanied usually by the
appearance of the first white winter feathers upon the abdomen and
flanks. The two white central tail feathers persist, in some cases at
least, until the end of the summer, though they are hidden by long
upper tail coverts. Whether or not these late retained feathers are
at once replaced with other white ones I do not know.

The above remarks all pertain to the adult male. The adult female
undergoes a more or less extensive molt, beginning late in July, follow-
ing the barred breeding plumage and marking a well-defined plumage
stage. She then acquires, above and below, finely mottled feathers like
those of the male, but this plumage is never (or at any rate very
rarely) acquired in its entirety before the white winter feathers
appear. Young birds of both sexes begin a replacement of juvenal
plumage with finely mottled feathers as in the adult, but here, too, the
white winter feathers appear before the first change is accomplished.
So quickly do the several molts follow one another during the summer
months, that it is not uncommon to find female birds in August with
remaining patches of white feathers from the previous winter, the
greater part of the body clothed in the barred breeding plumage,
some extensive areas of mottled feathers of the ‘‘winter plumage,
preliminary,’’ and some areas of new white feathers.

Lagopus leucurus leucurus (Swainson). White-tailed Ptarmigan

Oceurs, apparently not abundantly, at high altitudes. The pre-
dilection of this species for exposed, rocky ridges is reflected in the
local name ‘‘rock ptarmigan.’’ The few people we met who recognized
the existence locally of three species of ptarmigan called the true rock
ptarmigan by the name of ‘‘croaker.’’

I encountered the white-tailed ptarmigan on but one occasion, on
September 1, when a flock of from fifteen to twenty birds was flushed
on a rocky slope between the head waters of Spruce and McKee creeks,
at about 5000 feet altitude. Three specimens were collected (nos.
44725-44727), an adult female and a young male and female. In all
three the lower breast and belly are clothed in new white winter
plumage, the molt on those parts being direct from the barred breed-
ing plumage in the case of the old bird, from the juvenal plumage in
the young. Elsewhere these birds are entirely in the soft gray colors
of the ‘‘winter plumage, preliminary.’’ :