18 THE IMPORTANCE OF BIRD LIFE 



aquatic plants and often seeds, Similarily, 

 when a Cooper's hawk devours a granivorous 

 bird, the material in the crop of the victim is 

 scattered upon the ground, or is expelled later in 

 the feces of its slayer. 



Destruction of Vertebrates 



Having touched slightly upon insects and dis- 

 cussed the subject of limitation of vegetation, we 

 now arrive at the third mission in which birds 

 hold a trump card. This is the suppression of 

 vertebrates. 



Although the destruction of rodents properly 

 falls in the field of economics and will be dis- 

 cussed at greater length in the next chapter, birds 

 have an effect on other vertebrates which war- 

 rants a place here. Large hawks, eagles, and 

 owls exert considerable influence over the home 

 life of many medium-sized animals. The hawk- 

 eagles of South America subsist almost wholly 

 upon monkeys and other mammals that inhabit 

 the roof of the jungle. In other parts of the 

 world eagles capture fawn, young antelope, 

 sheep, goats, and even young wild pigs. Nor are 

 reptiles exempt. The secretary-bird of South 

 Africa is closely protected by law because of its 

 fondness for poisonous snakes. In our country, 



