338 



ELEMENTARY ZOOLOGY. 



including the various thrushes (Fig. 144), the robin, the 

 bluebird, and the mocking-bird. 



332. Relation to Nature. It will be seen from the 

 foregoing description that the birds, while much alike 

 in fundamental structure, have succeeded in adjusting 



FIG. 144. Wood thrush (Hylocichla mustelina) . Female, one-half 



By Folsom. 



themselves to a remarkably varied life. The food, the 

 special environment, the locomotion, the nesting and 

 breeding habits, the relative length and size of the various 

 external structures, as neck, beak, legs, toes, claws, wings, 

 and tail, are subject to remarkable variations in meeting 

 the various demands of life. The number of species 



