ADAPTATIONS OF BIRDS FOR FOOD-GETTING 121 
which act as snow shoes, enabling it to run over the snow 
without sinking in. This adaptation disappears in the spring 
when the need for it no longer exists. In the case of the 
ptarmigan of the Western States, the winter plumage is white 
but the summer plumage is brown and gray. The white 
plumage matches the snow, making it more difficult for 
enemies to find the bird, and the white plumage is warmer 
than any other color. 
99. Adaptations of Birds for Food-getting. — These adapta¬ 
tions are chiefly seen in the beak and the feet. The hooked 
beak of the eagle is an adaptation for seizing and tearing. 
The long beak of the kingfisher is an adaptation for spearing 
fish. The beak of the cowbird is short and thick for breaking 
up seeds. The hairy woodpecker has a chisel-like beak for 
cutting holes in trees, where it finds its food. The woodcock 
has a flexible beak for probing in the mud (Figure 111). 
The strong feet and curled claws of the hawk are adapta¬ 
tions for seizing and holding its prey. The long toes of the 
gallinules allow them to walk over floating leaves in search 
of food. The woodpeckers have two toes in front and 
two behind which give them a firm hold on the bark while 
they are driving holes in the tree. The loons have webbed 
toes that they may swim under water and pursue fish. The 
domestic fowl has large strong nails to assist in scratching 
for its food. The beaks and claws of most birds will be 
found fitted for the kind of work that the birds must do, 
either to procure food or to protect themselves. 
100. Public Museums. — As man came to occupy the 
land, the forests were cleared away and the ground used 
to produce food for man and domestic animals. This 
tended to drive the wild life, native to such regions, into 
the mountain fastnesses where they were free to live. 
This resulted in many of them becoming extinct even when 
they were of great use to man. The bison and brook-trout 
are two good examples (Figure 61). The expense of collect- 
