COOPERATIVE CAMPAIGNS FOR THE CONTROL OF 

 GROUND SQUIRRELS, PRAIRIE-DOGS, AND JACK 

 RABBITS. 



By W. B. Bell, 

 Assistant Biologist, Bureau of Biological Survey. 



NATIVE RODENTS cause losses of crops in the United 

 States amounting to many millions of dollars each year. 

 Everywhere present, when a region is first settled they per- 

 sist and frequently adapt themselves in a surprisingly short 

 time to feed upon cultivated crops. Because of their great 

 abundance and remarkable fecundity they have resisted suc- 

 cessfully the sporadic individual efforts of the tillers of the 

 soil to eradicate them. Their long-continued inroads into 

 the profits of the farmer, when not disregarded altogether, 

 are too frequently looked upon as inevitable. Often the mar- 

 gin destroyed by them makes the difference between a com- 

 fortable profit and a wretched failure. Even experienced 

 agriculturists too commonly fail to realize the enormity of 

 their cumulative exactions upon the financial resources of 

 the country and the possibility of applying more intelli- 

 gently the means of combating them. 



Farming operations tend to provide ideal conditions for 

 the abnormal multiplication of those rodents which readily 

 turn from supplies of native vegetation to feed upon grow- 

 ing crops or stored agricultural products. Indiscriminate 

 destruction of their natural enemies, the hawks, owls, and 

 predatory mammals, disturbs still further the balance in 

 nature by removing these checks upon them. Hence, the 

 numbers of these animals have increased, as have also the 

 losses inflicted by them, in spite of individual attempts to 

 control them. Under these conditions lands cleared of the 

 pests by progressive farmers soon become reinfested by inva- 

 sion from adjacent areas where less thrifty practices permit 

 these rodents to remain and multiply. 



THE BOUNTY SYSTEM INADEQUATE. 



The payment of bounties for the destruction of naftive 

 rodents has cost States, counties, and townships excessive 

 sums annually. In 1916 counties in Iotw .paid $77,279 in 



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