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- 
