364 ELEMENTARY ZOOLOGY 



curving nails, of the hawks and owls and other birds of 

 prey. In all these cases the fitness of the structure of the 

 foot to the special habits of the bird is apparent. 



Similarly the shape and structural character of the bill 

 should be noted, as related to its use, this being chiefly con- 

 cerned of course with the feeding habits. Note the strong 

 hooked and dentate bill of the birds of prey; they tear 

 their prey. Note the long slender sensitive bill of the 

 sandpipers ; they probe the wet sand for worms. Note 

 the short weak bill and wide mouth of the night-hawk 

 and whippoorwill and of the swifts and swallows; they 

 catch insects in this wide mouth while on the wing. Note 

 the flat lamellate bill of the ducks; they scoop up mud 

 and water and strain their food from it. Note the firm 

 chisel-like bill of the woodpeckers; they bore into hard 

 wood for insects. Note the peculiarly crossed mandibles 

 of the cross-bills ; they tear open pine-cones for seeds. 

 Note the long sharp slender bill of the humming-birds; 

 they get insects from the bottom of flower-cups. Note 

 the bill and foot of any bird you examine, and see if they 

 are specially adapted to the habits of the bird. 



The tongues and tails of birds are two other structures 

 the modifications and special uses of which may be readily 

 observed and studied. Note the structure and special use 

 of the tongue and tail of the woodpeckers; note the 

 tongue of the humming-bird ; the tail of the grackles. 



Flight and songs. The most casual observation of 

 birds reveals differences in the flight of different kinds, so 

 characteristic and distinctive as to give much aid in 

 determining the identity of birds in nature. Note the 

 flight of the woodpeckers ; it identifies them unmistakably 

 in the air. Note the rapid beating of the wings of quail 

 and grouse; also of wild ducks; the slow heavy flapping 

 of the larger hawks and owls and of the crows ; and the 

 splendid soaring of the turkey-buzzard and of the gulls. 



