INTRODUCTION xvil 



The good they do in cases of insect plagues, 

 like that of the grasshopper scourge in Nebraska 

 and Kansas, is still more marked. Then, as self- 

 constituted militia, they fly to the scene of action 

 and make way with the rioters. An interesting 

 case of this kind was seen in an old orchard in 

 Illinois. The cankerworm had so taken posses- 

 sion that the orchard looked almost as if burned 

 over. Forty different kinds of birds assem- 

 bled in the place to feed upon the worms. One 

 hundred and forty-one of the birds were shot and 

 the contents of their stomachs examined, and 

 more than one third of their food was found to 

 be canker worms ; the feathered army was simply 

 wiping out the horde of worms. A similar case 

 occurred in Massachusetts, and after the visit of 

 the birds a good crop of apples was raised in the 

 orchard which had been devastated. 



It is well known that, of the various groups of 

 birds, the majority live upon insects ; and while 

 most insectivorous birds probably take some use- 

 ful insects, as far as they have been studied but 

 few eat enough to weigh against the large num- 

 ber of harmful insects they live on throughout 

 the year. Among the insect-eaters are the Fly- 

 catchers, Warblers, Woodpeckers, Nuthatches, Ori- 

 oles, Goatsuckers, Humrningbirds,Tanagers, Wax- 

 wings, Gnatcatchers, Kinglets, Vireos, Thrushes, 

 Wrens, Titmice, Cuckoos, Swallows, Shrikes, 

 Thrashers, Creepers, and Bluebirds. 



