DIVERS, GREBES, AND CORMORANTS. 181 



adult plumage of the Gannet is white, tinged with 

 buff on the head and neck, except the primaries, 

 which are black. The bare skin round the base of 

 the bill is blue. The bird probably does not attain 

 its white plumage until nearly four years old, passing 

 through a series of mottled stages of black, brown, 

 and white. The young are hatched blind and 

 naked, but eventually become clothed in dense white 

 down. Other structural peculiarities are the closed 

 nostrils, and the subcutaneous air cells almost cover- 

 ing the body, which the bird can fill with air at will, 

 as they communicate with the lungs. Whether seen 

 at its nest, or when fishing at sea, the Gannet is a 

 remarkably interesting bird. As may naturally be 

 inferred, a bird so light and buoyant as the Gannet 

 does not obtain its food by diving. It is incapable 

 of submerging itself even for a little distance, except 

 by gaining sufficient momentum from a plunge 

 headlong from some distance in the air. Neverthe- 

 less, the Gannet feeds exclusively on fishes, which 

 it catches almost like a Tern, by dropping from a 

 great height and seizing or impaling them with its 

 strong bill. The Gannets follow the shoals of fish 

 as they swim near the surface. First one bird, and 

 then another, will be seen to poise itself, and then, 

 with closed wings, to dash downwards, glinting like 

 a piece of white marble in the sun, into the sea, 

 disappearing for a moment, then rising again into 

 the air to prepare for another descent. Many 

 Gannets at these times may, perhaps, be seen swim- 



