20 



serve to give some idea of the great influence that birds exert 

 on the prevalence of insect life. 



The remarkable appetites of birds serve to make them sig- 

 nally useful when they destroy our insect enemies, but pro- 

 portionately harmful when they feed on grain, fruit or other 

 crops. The chief crop injuries attributable to birds occur 

 when, during migration, birds gather excessively in one locality. 

 To utilize in full the services of birds, and to minimize the 

 losses that they cause, we should adopt toward them the policy 

 of the natives of India, who refrain from killing birds, but use 

 ingenious devices to frighten them away from fields of ripening 

 grain. It may be necessary at times to kill birds to protect 

 crops or poultry, but such birds in New England as are com- 

 monly more injurious than beneficial may be counted on the 

 fingers of one hand. 



Crops and Trees saved from Destruction by Birds. 



The principal service of birds to agriculture consists in the 

 prominent part that they play perennially in the control of in- 

 sect pests. Modern agriculture, both intensive and extensive, 

 produces great crops of the same food plants year after year on 

 the same or contiguous tracts, thus occasioning an excessive mul- 

 tiplication of the insects that feed on those crops. Other crop- 

 destroying insects are introduced from foreign lands. Mean- 

 while the birds that feed upon them are destroyed by farmers, 

 gunners, boys, cats, dogs and other enemies or agencies intro- 

 duced by man, while their nesting places are broken up and 

 their natural food plants destroyed by the operations of agri- 

 culture. Under these circumstances we need not wonder that 

 the numbers of birds often are insufficient fully to copt with 

 our greatly increased insect enemies; or that, deprived of their 

 natural food, birds attack grain or fruit. Frequently it becomes 

 very evident that birds are not sufficiently numerous to keep 

 insect pests in check. Nevertheless, they suppress insect out- 

 breaks more often than is generally known. By increasing their 

 numbers we may render them still more effective. 



In presenting the following accounts of the suppression of 

 insect invasions by birds, one cannot always guarantee the 



