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102 University of California Publications in Zoology [Vou 30

We visited rock ptarmigan territory too late to find nests, but from
the actions of the birds as we saw them it would seem that the male
of this species is not a devoted and constantly attendant mate to the
hen, as is notably the case in the willow ptarmigan. The male rock
ptarmigans were gathered, two, three, or four together, while the
females bore the care of the young alone. Occasionally a female (pre-
sumably a non-breeding bird) was seen with several males. On
August 8 I did flush a flock consisting of at least one brood of large
young ones, and several adult males. This I took to be the beginning
of a general flocking together, as might be looked for at the end of
the summer.

The adult male taken on June 9 is still largely in winter plumage,
especially below. There are barred feathers on the throat and upper
breast, and the back is mostly clothed in summer plumage. Adult
males taken during the last week of July and early in August are in
summer plumage in as nearly perfect condition as it can probably
ever be found, though in all the rectrices are being renewed. In the
perfection of this plumage even the abdomen is partly or even entirely
clothed in dark-colored feathers, but usually a large white area persists
on the lower parts of summer birds. In some specimens old white
body feathers are being replaced by new white ones, showing that there
is not always an intervening dark summer plumage on parts of the
body that are dark on some birds.

The adult male rock ptarmigan does not seem to go through the
stage termed by Dwight (1900, p. 162) ‘‘second, or adult, winter
plumage (preliminary),’’ that is so well defined in the willow ptar-
migan. I am aware that the contrary has been argued (see, for
instance, the account of Lagopus ridgwayi by Stejneger [1885,
p. 195]), but whatever may be the facts as regards other forms of the
rock ptarmigan, in British Columbia the male bird of this species does
not exhibit two distinct plumages during the summer months. The
female does, and the fact that we collected male birds during the period
when the females (as well as both sexes of the willow ptarmigan) were
molting from one plumage stage to the other, enabled me to make
satisfactory comparisons of the different plumages. The first appear-
ance of the brown and black barred feathers upon the head, neck, and
upper breast in the male rock ptarmigan (early in June in northern
British Columbia) is followed so uninterruptedly by the spread of
more finely mottled feathers over the rest of the body, that these can
hardly be considered as two distinct plumages. Furthermore, the first