280 GENERAL SCIENCE 



Some kinds of birds of most beautiful plumage have become nearly 

 or quite extinct because of their use for millinery purpose's. 



The necks, legs, feet, wings, and bills in different kinds of birds are so 

 modified as to fit them for their special manner of life. It is an illus- 

 tration of the effect of environment upon animal life, and of adaptation 

 to needs. 



Birds raised entirely apart from any of their kind exhibit what is 

 called instinct in their skill in nest building, and in their migratory 

 habits. They do just as if they had been taught by the parent birds. 

 This transmission of traits from generation to generation, and the cer- 

 tainty with which these traits will be reproduced in succeeding genera- 

 tions, is one of the marvels of all plant and animal life. It is of the 

 utmost importance, too, in mankind. 



The migration of birds appears due very largely to failure in the food 

 supply, or to need for an improvement in it. 



The great value of birds as a check upon insect pests may be calcu- 

 lated in the vast numbers of insects that might have multiplied from 

 those destroyed early in the season when fruits and seeds are scarce as 

 food for the birds. 



Exercises 



1. Upon what do birds largely subsist? Account for their migrations. 



2. In what respects are birds (a) useful to men; (b) harmful? Name reasons 

 other than their usefulness for protecting birds and caring for them. 

 What exceptions are there to the rule "Protect the birds"? 



3. The extended use of the plumage of birds for millinery has resulted in 

 what conditions? What only has caused any considerable check upon 

 this evil? How is it that extreme cruelty is so often incident to the 

 collection of the plumage of birds for millinery purposes? 



4. What is meant by a "closed season" for game birds? 



6. Name various natural enemies of the song birds. Tell how some degree 



of protection against these may be afforded the birds. 

 6. How do birds make ample returns for the shelter afforded them in the 



trees about a home? 



