160 Dwieunt, Moult of Quails and Grouse. Apa 
Lagopus rupestris (Gme/.). Rock PTARMIGAN. 
ie ;: reinhardi (Brehm). REINHARDT’S PTar- 
MIGAN. 
Ps ° nelsoni S7ejz. NELSON’s PTARMIGAN. 
ee 5 atkhensis (Zurner). TURNER’S PTARMIGAN. 
ds eh townsendi £//i0t. TOWNSEND’s PTARMIGAN. 
The series of Rock Ptarmigans and near allies, though smaller 
and less complete than that of /agopus, shows conclusively that 
there is an analogous sequence of moults and plumages. The 
dusky buff-barred juvenal and nuptial stages of plumage are fol- 
lowed by an intermediate stage when mottled dusky gray feathers 
are assumed more or less abundantly on the upper parts of the 
head and the breast, while coincidently the wings, abdomen, flanks, 
legs and feet assume a white plumage which is retained for a twelve- 
month. The dusky gray plumage, however, is scarcely donned 
before a supplementary moult begins, radiating from the usual 
points of departure on the sternal bands, and from the numerous 
other points on the back and head where other moults regularly 
begin. This supplementary moult advances down the middle of 
each sternal band or a little to its inner side, beginning on the 
sides of the breast and radiating laterally, so that the mesial bor- 
ders of these feather tracts lose their parti-colored feathers earlier 
than do the borders beneath the wing. There is usually only a 
sprinkling of feathers of the intermediate stage on these tracts, 
together with ¢wo sorts of feathers that originated at the previous 
postnatal or postnuptial moults, according to the bird’s age, all of 
which are now replaced by the growth of new white ones, as 
presently are all dusky feathers elsewhere. A pure white winter 
plumage with black tail results from ¢wo moults just as in /agopus. 
No evidence of color changing without moult is to be found. 
At the beginning of the short Arctic summer a prenuptial moult 
of varying extent takes place, apparently birds of localities where 
the snow is ever present undergoing a very limited renewal of 
grayish dusky feathers. I have discussed the corresponding 
changes of plumage so minutely under /agopus, that I need not 
repeat here except for clearness. The remarks apply to rfestris 
except when otherwise specified. 
