i ie DwicutT, Moult of Quatls and Grouse. 147 
spotted under wing-coverts have replaced the gray ones of the 
juvenal stage. Numerous October specimens examined have 
lost all traces of moult except in some of them on the border 
line between the breast and throat. The ‘ruff’ of young males 
is not so deep a black as that of adults and the barring of the 
lower parts is less extensive and somewhat paler, but plumage 
characters cannot be absolutely depended upon to distinguish 
young from old. 
first Nuptial Plumage, acquired by a limited prenuptial moult 
confined to the head and chin. A specimen of sadinz (Amer. 
Mus. No. 47282, British Columbia, June 2) shows numerous 
pin feathers on the chin, throat, sides of head and forehead. 
Another sadimi (Amer. Mus. No. 47279, ¢, British Columbia, 
May 20) also shows a few pin feathers. <A few other spring and 
summer birds of other races have been obtained too early or too 
late (z. ¢., March or June) to show positive signs of moult. 
Later plumages are repetitions of the winter and summer dress. 
Lagopus lagopus (Zzzz.). WILLOW PTARMIGAN. 
cs ce alleni Sfejn. ALLEN’s PTARMIGAN. 
The series of Ptarmigans in the American Museum of Natural 
History and in the U. S. National Museum, together with speci- 
mens from Alaska kindly loaned me by Dr. Louis B. Bishop, and 
a few in my own collection, illustrates most effectively all the 
plumages and moults of these Arctic birds. The study of this 
material, amounting to nearly two hundred specimens, now enables 
me to explain the parti-colored plumages of these birds, a matter 
that has long baffled investigation and given rise to a belief that 
the individual feathers themselves change color without being 
moulted. It has also been believed by some that Ptarmigans 
moult continuously and in a hap-hazard way during the whole 
year. All of these ideas have arisen from a misconception of 
the facts, which show that the feathers supposed to be changing 
color or pattern are of that particular color and pattern at the 
time they first expand, that the continuous moult resolves itself 
into definite periods, and that the feather growth is systematic, 
differing in no respect from that of the rest of the Grouse. The 
