THE MOULTING OF THE KING PENGUIN. 
117 
are descended from a common ancestor. Seeing that the head of Wilson’s immature 
King Penguin is relatively small, it may perhaps be assumed that immature 
penguins with pale yellow patches have moulted prematurely — moulted when they 
had only reached the phase in the ancestral history characterised by a blue-grey 
patch on the crown of the head. 
When the young King Penguins in the Scottish Zoological Park had completely 
shed their down they very closely resembled in their plumage one of the newly 
moulted old birds which accompanied them from South Georgia. Instead of developing 
a patch of blue-green on the top of the head, one of them soon acquired the peculiar 
bloom usually associated with mature birds. More remarkable still, as the greenish- 
yellow sheen developed on the head, the sheath of the mandible gradually changed 
from the dark tint characteristic of immature birds to a lighter tint, and some weeks 
later it assumed the orange-pink colour usually associated with mature birds. In the 
second young bird there was no hint of a greenish sheen on the top of the head in 
1914, neither is there any suggestion of this subtle greenish gloss in 1915. # In all 
probability the differences noticed amongst birds which have just lost their down are 
due to late-hatched birds moulting at or about the same time as birds hatched during 
the early part of the breeding season. 
The Moulting of the Immature and Adult Plumage. 
(l) Time of Moulting. 
From the observations made by Dr Wilson during the Discovery expedition, 
we know that the Emperor Penguin breeds during the winter ; that the eggs are laid 
on sea ice early in J uly — the darkest and coldest month of the Antarctic winter, — and 
that the young are hatched about the end of August, and moult at the end of 
December when about four months old ; and that the adult birds, having finished all 
their duties to the young, leave them to themselves and retire southwards in January 
and February to take up their retreat and moult in safety on fast ice. The Emperor 
Penguin, even when moulting, never sets foot on land. The immature Emperors 
when on the point of moulting also “ wander south to find fast ice, on which they 
remain while the process lasts/knowing that in the disintegrating ice-pack they 
might be forced to take to the water when it would be highly inconvenient for them 
to do so.” t A young Emperor brought on board the Discovery in Lady Newnes 
Bay shed its immature coat and donned the adult plumage and all the distinctive 
characters of the fully adult bird when seventeen months old — this bird probably 
began to moult in the middle of January. 
The rookeries of the King, unlike those of the Emperor Penguins, are on land, 
* In the surviving old bird from the Antarctic, a greenish sheen has never made its appearance on the top of 
the head. 
t Wilson, loc. cit., p. 19. 
