Vol. XVII 
1g00 
DwienT, Moult of Quatls and Grouse. AT 
It is almost impossible to assign a time for the acquisition of 
the juvenal plumage. Birds about one third grown will still have 
downy chins, foreheads and abdomen and the tail barely showing, 
while the plumage elswhere is well developed, except the oppo- 
site ends of the row of remiges, where the quills are only partly 
grown... At about this time, the first signs of the postjuvenal 
moult may be found in the replacement of the tenth primary by a 
new one, the first of the winter plumage. This moult may in- 
volve five or six primaries before it is noticeable upon the body 
at either side of the breast. Birds are about one half grown 
when this point of development is reached, perhaps three weeks 
or so old. 
The tendency is for the juvenal plumage to resemble somewhat 
that of the adult female, the sexes, asa rule, not being certainly 
distinguishable, both wearing, for instance in the crested species, 
a crest that is usually brown, which in the adult would be black. 
All colors are apt to be duller than those of the next plumage, 
more uniformly colored, sometimes slightly barred or mottled 
feathers preceding the rich tints of the winter dress, which is 
practically alike in the young and old of nearly all species. 
3. Hirst Winter Plumage. — This third stage is reached by a 
postjuvenal moult which is complete except for the retention of 
the two distal primaries of each wing, and the plumage assumed 
is scarcely to be distinguished in any of the species from that of 
the adults in winter plumage. The completeness of the postju- 
venal moult and the early acquisition of adult plumage simplifies 
all questions of plumage except in the Ptarmigans. ‘They, how- 
ever, assume a dress which is white except upon the head, throat, 
outer part of the sides and the back. The supplementary postju- 
venal moult peculiar to them follows quickly and involves only the 
feathers of the dark areas. As the postjuvenal itself is scarcely 
complete before the supplementary one begins, it is not surprising 
that a plumage made up of feathers of three different periods of 
growth should have given risé to much discussion in explanation of 
the phases of dress through which these birds pass, there being a 
preliminary and a supplementary stage of the winter plumage. 
The difficulty is to draw the line between the different stages of 
plumage which, especially in the young bird, almost insensibly 
blend one into the other. 
