ea Dwicut, Moult of Quails and Grouse. 161 
Natal Down.—It is difficult to distinguish the chicks from 
. those of /agopus, but they are usually paler and grayer. 
Juvenal Plumage, acquired by a complete postnatal moult. 
Much duskier, and more barred, with less rusty tinge than the 
same stage of /agofus. Two birds, apparently rezhardi (Amer. 
Mus. Nos. 64133 and 64134, Greenland, July 28), about one 
third grown, still retain natal down on the chin, throat, mid- 
abdomen, legs and feet, but have already acquired four partly 
developed white proximal primaries of the winter dress. The 
first and second juvenal primaries are white, partly grown, the 
rest dusky. ‘The juvenal brownish tail is not fully grown. 
First Winter Plumage (preliminary), acquired by a fairly com- 
plete postjuvenal moult excepting the first and second primaries. 
The wings (except the median coverts and inner remiges) become 
white together with the abdominal wedge of the ventral tract and 
all posterior to it including the flanks, legs and feet; while the 
head, throat, breast, sides and back become more or less dusky 
according to the extent of the renewal in different individuals and 
probably according to the latitude. These feathers are of the 
type shown by Plate I, Figs. 2, 3 and 10, but dusky instead of 
reddish as in /agopus. The black rectrices are acquired at the 
postjuvenal moult. 
A number of specimens show the later stages of this plumage 
with the quickly ensuing change into the wholly white dress. It 
will suffice to cite a few. One (Amer. Mus. No. 67883, Sitka, 
Alaska, Sept. 15) has completed the postjuvenal moult of the 
wing except the third primary which is only half grown. The 
dusky preliminary dress prevails above and on the head and 
throat, with white feathers of the supplementary dress appearing 
on the throat, chin, back, tail-coverts and sternal bands, the last 
largely renewed by the supplementary moult which has not yet 
reached some parti-colored juvenal feathers at one border and 
both juvenal and preliminary winter ones at the other. The 
white of the mid-breast, abdomen, flanks, legs and feet is part of 
the preliminary dress. Another (Amer. Mus. No. 64130, @, 
Greenland, August 26) is more advanced, showing many white 
feathers of the supplementary stage. Other specimens (Amer. 
Mus. Nos. 66878, 66881, 2, and 66882, 9, Alaska, Sept. 15) are 
