224 BIRD WATER TRESPASSERS. 



It can dive to some depth and for some distance, 

 as is proved by the fact that it is sometimes caught in 

 the fishermen's nets, having been entangled in them 

 when chasing its prey. But it does not catch fish like 

 the birds which have already been mentioned. Their 

 usual plan is to swim about on the* surface of the water, 

 then to dive, and, if they are successful, to come to the 

 surface, swallow their prey, and dive again. 



The Gannet, on the other hand, takes its prey much 

 after the fashion of the common kingfisher. It hovers 

 over the sea at some height, watching for fish. When 

 it sees a chance, it darts down into the water with 

 wonderful force, and almost invariably comes up with 

 the fish in its mouth. The osprey catches fish in a 

 somewhat similar manner, except that it does not dive 

 beneath the surface, and catches the prey with its 

 claws, and not with its beak. 



It is evident, therefore, that the hawk does not 

 strike the water with such force as does the Gannet, 

 and, indeed, keeps itself, by its outspread wings, from 

 being dragged below the surface by the weight of the 

 fish which it has taken in its claws. But the Gannet 

 hurls itself into the water with such force that it 

 would injure itself by the shock, were it not protected 

 in some manner from the collision with the water. 

 This object is attained in the following simple and 

 effective manner : 



I have already mentioned that the bones of flying 

 birds are hollow, and communicate with the lungs. In 

 the Gannet there is a further development of the idea. 

 Not only are the bones hollow, but the skin is hollow 

 also, if I may use such an expression. It is perforated 



