560 MAN CONTROLS HIS ENVIRONMENT FOR WEALTH 



and we can find little or no good to say about them. The English 

 sparrow is the greatest bird pest, for reasons given above. The 

 cowbird never builds a nest nor cares for her young. She lays 

 her eggs in the nests of smaller birds, usually warblers, where later 

 ihe young cowbirds cause the death of the rightful inhabitants of 

 the nest. Cooper's hawk, the sharp-shinned hawk, and the great 

 horned owl kill smaller, beneficial birds. 



Practical Exercise 28. Try to find a nest containing eggs and watch the de- 

 velopment of the young over a given period. Report your findings to the class. 



Practical Exercise 29. Make a table for your workbook in which you name 

 as many local birds as you can. List them as useful, harmful, or harmless, and 

 in a fifth column give evidence for your statements. 



Practical Exercise 30. Make a study of the feeding habits of some one bird 

 and report on it. 



Practical Exercise 31. What methods of protection of birds do you find in 

 your community ? What means have you taken to protect birds that live near 

 your home? 



Self-Testing Exercises 



The robin is about (1) (2) long, (3) 



(4) on breast, (5) on wings, and (6) on head. 



The chickadee may be recognized by its (7). It is about 



(8) inches in length, head and throat (9), abdomen 



dirty (10). The American goldfinch is (11) ; the 



bluebird (12) in general color. The yellow warbler is about 



(13) inches long and has no (14) on its (15). 



The barn swallow is between (16) and (17) inches 



long, dark (18) (19) above, breast and abdomen 



(20), tail deeply (21). The Baltimore oriole is about 



(22) inches long . The male oriole is brightly colored with 



(23), with throat, and upper back (24). Owls may 



usually be told by the (25) beak and prominent (26) 



eyes. 



PROBLEM Vin. WHAT IS THE ECONOMIC IMPORTANCE OF 



INSECTS? 



Useful insects. We have learned that many insects pollinate 

 flowers ; that in many cases insects are preyed upon, and supply 

 an enormous multitude of birds, fishes, and other animals with 

 food. Dr. Forbes of the University of Illinois estimates that 

 many of the smaller fresh-water fishes consumed over fifty per cent 

 insect food, mostly larvae. 



