58 EDWARD A. WILSON. 
north by sea or ice as opportunity offered. One thing they would on no account risk, 
namely, to enter the water during the moult, and so they took the latter alternative 
and waited, fasting, where they were. 
The feathers that were being shed were old, worn, and faded, giving the bird a 
brownish look all over. They were shed, moreover, not feather by feather, but in 
spurious sheets, large numbers of them being held together, as Mr. Pycraft has pointed 
out to me, by the cohesion of the barbs and barbules. The size of the bird as the old 
coat loosens is prodigious compared with the sleek and slim appearance of the newly 
moulted one, for not only do the old feathers stand out at right angles to the skin, but 
the thick layer of fat in which the new feathers are embedded is still below the skin. 
As the new feathers develop, this layer of fat diminishes, and the difference in the close 
fit of the glossy blue-black plumage and the old dishevelled loose brown coat is more 
than ever marked. 
There are, therefore, to recapitulate the various plumages and moults. 
1. Downy plumage carried for one month from Dec. 15th to Jan. 9th, and in this, 
I understand from Mr. Pycraft, there are two distinct phases. In the light of this 
observation the variation of the first phase, which I have noticed above (see page 51), 
in the colour of the youngest chicks is the more interesting. The silvery aspect lasts 
only for the first week or less, and during this stage the silvery-white character of 
the down and the black head strongly suggest the colouring of the Emperor Penguin’s 
young. One is inclined to think in consequence that the colouring of the Emperor’s 
chick is on the whole more primitive than that of the King Penguin’s chick. This 
transitory silver grey phase in Pygoscelis adeliz no doubt corresponds to the white 
phase of the chick in the Pygoscelis antarctica, as described by Mr. Eagle Clarke, and 
the second smoky phase of P. adeliez with the second phase of the chick of 
P. antaretica. 
The nestling’s down is moulted between Jan. 9th and 16th, and the ensuing juvenile 
white-throated plumage is carried for thirteen months from Jan. 16th to Feb. 15th of the 
following year. 
The next moult, to the black-throated adult plumage, follows between Feb. 15th 
and March 7th. 
It is possible that a year more is spent in the pack-ice after the adult plumage 
has been acquired, and that these are the black-throated birds which are seen 
in such numbers in the pack-ice in January, many hundreds of miles away 
from the business of the nesting colonies. If this be so it would postpone the 
commencement of breeding till the end of the bird’s third year, and this is quite 
possibly the case. One thing is certain, that having assumed the livery of the adult, 
which is identical for male and female by the month of February, they wear it without 
much deterioration throughout the winter in the pack. The moult in all stages of 
immaturity is autumnal, and being also an autumnal moult in the adult, it may be 
called post-nuptial. 
