4 o6 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



the natural enemies of some of the insects, and thus upsetting 

 the balance that had been established in nature, is accountable 

 for a large measure of this increase. 



The part that birds play in the control of the insect pests of 

 forest, orchard, garden and field is of much more importance 

 than is usually realized. Many species of birds feed chiefly 

 upon insects. From an examination of the stomach contents 



FIG. 1 88. Phoebe, a well known flycatcher, 90 per cent, of whose food 



consists of insects. 



of large numbers of birds it has been estimated that insects 

 form about 96 per cent, of the food of flycatchers in some 

 regions, 95 percent, of the food of wrens, 94 per cent, of warblers, 

 65 per cent, of woodpeckers and meadow-larks, and more than 

 25 per cent, of the native sparrows. Swifts, swallows, titmice, 

 crows, jays, blackbirds and many others feed largely on in- 

 sects. As many as 3000 to 5000 insects have been taken from 

 the stomach of a single bird. Of course many beneficial insects 

 are eaten with the injurious ones, and some of the birds also 

 take toll of fruit in the orchard or grain in the field but with 



