NESTS AND EGGS. 387 
were frequently killed in one day, and it was not till the next 
year that they were exterminated. 
In some islands the nests of marine birds are so close together 
that it would hardly be possible to take a step without crushing 
an egg; and it often happens that a bird will lay its egg in 
another bird’s nest. Thus, Naumann found the egg of a long- 
tailed sea-swallow in the nest of an oyster-catcher, and the egg 
of the latter bird in a penguin’s nest. Yet every mother knows 
THE GREAT PENGUIN. 
(Penguinis intpennis.) 
her own eggs, and never makes a mistake. We should think this 
incredible, if the instinct of animals had not accustomed us to 
marvels. 
Most of the eggs of aquatic birds have one end larger than the 
other, resembling in this respect the egg of the common fowl. 
Those of the cormorant are long, and both the ends are small. 
But the eggs of some of the penguins are quite round. The 
eggs of the cormorant are small compared to the size of the bird ; 
those of the guillemots, on the contrary, are large. The capuchin 
Z2 
