200 ANIMAL ACTIVITIES. 
and the jaws of a frog or fish. Noticeable, too, is the 
resemblance between the bill of the bird and that of the 
turtle. The hard toothless mandibles, however, are well 
fitted for the purpose of securing the insects and seeds on 
which most birds feed. Before man invented tweezers, 
the woodpeckers pried into the bark of trees and pulled 
out the hidden insects with their long, strong pliers. 
These illustrations show some of the forms the beak 
takes to make it a better tool for procuring the particu- 
lar kind of food on which the bird lives. In addition 
to its other uses the beak often serves as a hand. 
Birds and Insects. Insect-eating birds devour tons 
of destructive pests in our orchards and fields. It has 
been estimated that a single chickadee may destroy 
mre than a hundred thousand canker-worm eggs in 
Fic, 156.—The Digestive Organs of a Bird. a, cesophagus; 4, crop; 
C, stomach; ¢, gizzard. 
one day. Even crows feed on insects more than on 
corn. Hawks and owls keep in check field-mice and 
frogs, gulls clean the shores of decaying matter, and 
many of the smaller birds live on the seeds of noxious 
weeds. The importance of preserving bird life cannot 
be easily overestimated. 
