THE ADELIE PENGUIN. 43 
had crossed this extensive track of guano, from the pure air of the barrier plain, the 
tests which we applied for the 24 hours which included the polluted air, showed a 
strength of 3 degrees of ozone, compared with a strength of 10 to 12 degrees on 
other days for half that number of hours. 
It may be surmised, therefore, that the sanitary condition of these rookeries is 
open to considerable criticism, and the place would be unbearable were it not for the 
fact that the winds are constant, and the temperature of the air in the summer months 
always, with the exception of one or two days in the year, below the freezing 
point of water; where dark rock is exposed it will rise a few degrees, but only from 
contact with the rocks which have absorbed heat from the rays of the sun. The dry- 
ness of the air, moreover, is a powerful agent in the prevention of such nuisance as 
would otherwise arise from so great an abundance of dead bodies and other organic 
refuse ready to decay, and the remains of a penguin torn to pieces by the skuas will 
generally dry before it really decomposes. 
The quantity of crustaceans brought in during the day to such a rookery as that 
which exists at Cape Crozier or Cape Adare must be immense, for parents hurry in 
ashore from one end of the twenty-four hours to the other without cessation, their 
stomachs loaded with a mess of shrimps (see figs. 29, 30, p. 40; also fig. 32, p. 42). 
Chickens by the hundred stand in little groups of twelve or twenty, now in a state 
of bulging repletion, now in a ravenous hurry chasing some unfortunate adult but 
lately arrived with spoil from the open sea. 
One may, therefore, infer from the uniform colour of the thin layer of guano in 
every Adélie Penguin rookery that these red crustaceans do form their staple diet ; but 
at Cape Royds I have known them eat small fish, some three or four inches long, and, 
no doubt, they also feed on cephalopods, the beaks of which are often found in their 
stomachs. Beyond the remains of fish, cephalopods, Huphausiz, and other crustaceans, 
an invariable concomitant in the stomach of this bird is a collection of small pebbles, 
swallowed no doubt, for the purpose of reducing to a pulpy mass the indigestible 
parts of the crustaceans. That these pebbles are very necessary may be gathered from 
their constant presence in the stomach. There is no separate crop or gizzard, as such, 
in penguins, where the stomach forms one large undivided muscular sac capable of 
great distension. 
The chicken is entirely dependent upon its parents for food from the time it 
leaves the ege until it has completely shed its down and has assumed a feathering 
which enables it to enter the water. Undoubtedly it requires a very large supply of 
food, for its growth is rapid and the state of repletion which eventually brings the 
chicken to consider that it has had enough is not readily arrived at. One wonders how 
the young that are hatched out on the summit of such mountainous heights, nearly 
a thousand feet above the sea, can ever obtain a sufficiency of food. Yet they are as 
well grown and as healthy there as they are at the sea level, thanks to the untiring 
efforts of their parents, who form a constant stream passing up and down the sides 
VOL, IL. I 
