578 



BIOLOGY AND HUMAN LIFE 



the farmers took up arms and killed the bird off. The following 

 year, however, the absence of the blackbirds enabled the locusts 

 to multiply so rapidly that many of the grain crops were ruined. 



BIRDS IN RELATION TO MAN 



The food of birds must be studied 



Observation of bird habits 



Examination of contents of birds' stomachs 

 Economic importance of birds' eating habits 



Favorable to man 

 Destroy vast numbers 



of insects 

 Destroy many rodents 

 Destroy snails 

 Destroy weed seeds 



3. Dangers to birds 



Wanton shooting or stoning 

 Unscientific egg collectors 



(nest robbers) 

 Pothunters 

 Plumage hunters 

 Red squirrels 

 Cats 



4. Protection of birds 



Unfavorable to man 

 Eat grain 

 Eat fruit 



Eat eggs of other birds 

 Eat young of other birds 

 Eat domestic birds (chickens) 

 Eat frogs 



(Skunk ; weasel ; fox ; raccoon) 



Telegraph wires 



Lighthouses 



Disappearance of nesting places 



by growth of cities, cutting 



down of trees, etc. 



