94 University of California Publications in Zoology [Vou 30

Dwight’s paper) aceord with his statements, I believe, in every par-
ticular. Details here given are amplified in the belief that such studies
from all parts of the range of the willow ptarmigan.are necessary to a
thorough understanding of geographical variation in this species.

LIST OF THE NORTH AMERICAN SUBSPECIES OF THE WILLOW
PTARMIGAN (LAGOPUS LAGOPUS)

. Lagopus lagopus alleni Stejneger. Allen Willow Ptarmigan.
Lagopus lagopus ungavus Riley. Ungava Willow Ptarmigan,
Lagopus lagopus albus (Gmelin). Southern Willow Ptarmigan.

. Lagopus lagopus alascensis Swarth. Alaska Willow Ptarmigan.
Lagopus lagopus alexandrae Grinnell. Alexander Willow Ptarmigan,

a

Lagopus rupestris rupestris (Gmelin). Gray Rock Ptarmigan

Thirteen specimens of rock ptarmigan (nos, 44712-44724) were
collected by myself in the Atlin region, including seven adult males,
two adult females, and four young birds. Brooks’ Atlin series com-
prised about as many, similarly apportioned, and he later (September
11) collected at White Pass summit four additional specimens, two
adult females and male and female immature.

The ptarmigans form a group of birds that offers many difficulties
to the systematist. The rapid and continuous changes of plumage
undergone by any one bird during the summer months, together with a
rather wide range of individual variation among specimens from any
given locality, are puzzling features in themselves, still further compli-
cated by other differences due to sex and age. Then, ptarmigan, and
the rock ptarmigan in particular, are not well represented in collec-
tions, inhabiting, as they do, relatively remote and inaccessible regions.
So, more often than not, when specimens are brought together from
different sections they prove to be not comparable, and deductions
then can only be made by inference,

In a previous publication (Swarth, 1924, p. 333) I have commented
upon the appearance of a female rock ptarmigan from Nine-mile
Mountain, near Hazelton, British Columbia, a bird that differed appre-
ciably from the few Alaskan specimens available to me at that time.
The series we collected near Atlin, evidently in the same category as
the Nine-mile Mountain bird, seemed again so different from Alaskan
specimens as to justify more extensive comparisons,