LOCAL SUPPRESSION OF AGRICULTURAL 

 PESTS BY BIRDS. 



By W. L. McAtee, 

 Biological Survey, United States Department of Agriculture. 



[With 3 plates.] 

 INTRODUCTION. 



The general utility of birds in checking the increase of injurious 

 animals and plants is well understood. It must be admitted, however, 

 that while birds constantly exert a repressive influence on the num- 

 bers of the organisms they prey upon and even exterminate certain 

 pests locally, they are not numerous enough to cope successfully with 

 widespread invasions. 



Birds are prone to feed upon things which are abundant and easily 

 accessible. For instance, in elderberry season a very large number of 

 birds take elderberries; if May-flies swarm in a locality, practically 

 all of the birds there devour May-flies. Thus, under unusual condi- 

 tions, such as attend outbreaks of insect or other pests, birds very 

 naturally turn their attention to the plentiful and easily obtained 

 food supply, and the attack on a particular pest often is intensified 

 also by the flocking in of birds from surrounding areas. 



Hence birds at times materially reduce or even suppress severe 

 infestations of insects or other pests. Many striking instances of 

 such results of their work are recorded in the Old World, and the pur- 

 pose of the present paper is to present evidence relating to similar 

 cases in the United States. These instances are grouped with refer- 

 ence to the natural classes and orders to which the pests belong. 



From necessity the present paper is almost entirely a compilation, 

 and an effort has been made to exclude all instances of insect sup- 

 pression that seemed at all questionable. Nevertheless, the writer 

 can not vouch for the authenticity of the accounts of occurrences 

 which from the nature of the case he is unable to verify. 



SUPPRESSION OF INVERTEBRATE PESTS. 

 ORTHOPTERA (GRASSHOPPERS AND CRICKETS). 



Probably the most conspicuous insect outbreaks that have occurred 

 in the United States were those of the Kocky Mountain or migratory 



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