CHAPTER IV. 

 THE ANIMAL FOOD OF BIRDS. 



In the later pages of this volume the fact will become 

 apparent that a very large proportion of the food of birds 

 consists of insects, — the little creatures that fill the air, the 

 water, and the earth with life. Adult insects in general have 

 a body divided into three parts, called the head, the thorax, 

 and the abdomen, with three pairs of legs, one pair of an- 

 tennae, and usually two pairs of wings. They are grouped 

 together in certain natural orders, of which, from our present 

 point of view, the following are the most important. 



The order Orthoptera includes the crickets, grasshoppers, 

 cockroaches, locusts, and walking-sticks. These insects have 

 four wings, the front pair being thick and leathery, and the 

 hind pair thin and membranous. 



There are few groups of injurious insects that enter so 

 largely into the composition of the food of birds as do the 

 locusts, or short-horned grasshoppers, of the family Acridiidce. 

 The enormous destructive power of these insects is well 

 known, but our indebtedness to birds in checking their oscil- 

 lations is less generally recognized. No more convincing 

 proof of the latter, however, could be required than Professor 

 Samuel Aughey's records of the food of birds in Nebraska 

 during outbreaks of the Rocky Mountain locust, — records 

 which show that birds of all sizes and kinds turned their at- 

 tention to reducing the ranks of the invaders. Similar results 

 may be seen in many portions of the United States whenever 

 the local non-migratory species of locusts become unusually 

 abundant. The life-history of these insects is simple : the 

 eggs are deposited late in summer or early in autumn a little 

 below the surface of the soil ; the following spring they hatch 

 42 



