156 DwicuT, Moult of Quails and Grouse. 
points removes the brown feathers of the preliminary dress, 
together with such barred feathers as may have been skipped 
by the incomplete postjuvenal moult. As a result of the last 
two moults birds become wholly white except for the black 
rectrices, males and females being indistinguishable. Numerous 
winter specimens illustrate this plumage. In some cases brown 
feathers may persist throughout the long Arctic winter, which 
furnishes a period of rest from November to May, much needed 
perhaps after the active feather production of the short summer. 
A few specimens show this (U. S. Nat. Mus. No. 19887, 2, Great 
Slave Lake, April 4; No. 93060, 9, Alaska, April 1,.and No. 
94409, ¢, Labrador, March 21); the last is an unusual case with 
much brown. As old and young in full white plumage are indis- 
tinguishable except that adult males appear to have the crown 
feathers basally black, it can only be said that this dress is worn 
without change until April, as shown by several specimens (U. S. 
Nat. Mus. No. 50060, ?, Nulato, Alaska, April 12; No. 31660, 
Ft. Anderson, Canada, March 17; No. 98033, Bergen, Norway, 
March 15; Amer. Mus. No. 26889, Norway, “end of March”), 
and others with no indication of prenuptial moult up to that date. 
First Nuptial Plumage. — At the beginning of the brief summer 
which follows the long winter a partial prenuptial moult takes 
place, the extent of which appears to depend upon latitude, sex, 
and probably age. Part of the white body feathers are replaced 
by dusky or reddish ones, males assuming chiefly those of the 
type shown by Plate I, Figs. 5 and 6, the color being dull 
black barred or mottled with buff; females, those of the same 
type but more boldly barred with a richer buff, as shown by Figs. 
7,8 and 9. Females may now be distinguished with certainty 
from males for the first time by plumage characters, the barring 
being coarser and extending to the head, throat and breast, the 
feathers of which in the male are reddish brown, chiefly with 
narrow dusky terminal bands, and often tipped, on the chin 
especially, with white. It should be observed that parti-colored 
feathers basally or terminally white may be assumed at this 
moult on the internal borders of the sternal bands just as in 
juvenal dress, the abdominal wedge, flanks, legs and feet, retain- 
ing as a rule the white feathers of the winter plumage. The 
