THE ADELIE PENGUIN. 51 
and safely rear its young within a few yards of its own most sacred nest. I have seen 
the Adélie Penguin peck at and demolish its own egg which had a minute before been 
removed for inspection and had been put back under it, resenting the intrusion of what it 
evidently did not recognise as an egg at all. This, again, is no great sign of intelligence. 
Of its cleanliness there is nothing to be said but praise, for no bird on earth 
could possibly be more strictly clean than the Adélie Penguin. Hunt as one might, no 
parasite could be discovered amid the snowy feathers, nor any trace of dirt or adventi- 
tious matter. Within, it has, in common with all other birds and beasts of the 
Antarctic, abundant nematodes and quite a host of various forms of microbes, but 
externally it is scrupulously clean. 
There cannot now, I think, be much doubt that the Adélie Penguin takes not one 
year but two to reach maturity. It joins the breeding colony for the first time not at 
the end of its first but of its second year. Appearing from the egg in the middle of 
December, the colour of the little downy-coated nestlings is somewhat variable. 
Two are almost always hatched in each nest, and the interval which elapses between 
the laying of the two eggs, and so between the hatching of the two chickens, is 
sufficient to account for the discrepancy in their size. One is generally about twice 
the size of the other in the earlier stages of their existence. The eggs, varying in size 
from 6°45 cm. to 7°2 cm. in length, and from 5:0 cm. to 5°5 em. in breadth (this being 
the average of ten specimens), are rounded more or less equally at each end, of a white 
chalky texture without, and are of a green colour within, which by transmitted light is 
very marked. 
In the majority of the chickens the down is uniformly dark and sooty, but 
here and there in the progeny of quite normal parents one may find nestlings of so 
pale a grey as to be almost silvery white with blackish heads, possibly a reversion to 
an earlier type, and, at any rate, suggestive of the young of the Emperor Penguin, 
which perhaps represents the oldest stock of all. 
The changes undergone as the nestling grows are well described by Dr. Bowdler 
Sharpe in the report on the ‘Southern Cross’ collections, and, as he there says, the 
colour of the head is in all cases somewhat blacker in the earlier stages than the 
remainder of the body. But this difference gradually disappears, owing, no doubt, to 
the change in the nestling’s down, which Mr. Pycraft describes as taking place in this 
bird before it changes it for the immature first year’s plumage. The sooty black, as 
well as the silver grey, in such as have it, gives way before long to a smoky colour, 
which gets an old and dusty look by the time it begins to loosen on the under surface 
of the flippers. This moult begins on the abdomen and the thighs, where the white 
side stripes appear as the new feathers are disclosed (see fig. 37, p. 52); these parts being 
the first denuded simply because they bear the brunt of the wear and tear. Then it is 
shed from the face and head, round the bill, and round the tail. The upper breast 
and neck and back hold longest to the down, which will by now be clogged with ice 
and dirt and snow, all of which are abundant in the rookery from time to time. 
