260 ANNUAL REPORTS OP DEPARTMENT OP AGRICULTURE. 



of noxious rodents, except on the public domain, is effected through 

 cooperation with the States Relations Service of the Department of 

 Agriculture and the extension service of State agricultural colleges. 

 Cooperative campaigns of this kind are being conducted in North 

 Dakota, Montana, Idaho, Washington, Oregon, Wyoming, Utah, 

 Colorado, New Mexico, Arizona, and Virginia. This cooperation 

 has proved to be extremely successful, as is shown by the increased 

 number of farmers who join in the work each season. In addition to 

 the rodent pests which abound in the more arid States of the West, 

 several species are verj'^ destructive to certain crops and orchard 

 trees throughout the East, where demonstration work for their con- 

 trol has given good results. 



In order to secure accurate data as to the destruction of forage by 

 rodents on the open range, field trial plots have been inclosed for the 

 purpose in cooperation with the Forest Service and the Carnegie 

 Institution of Washington. It is already apparent that important 

 results will be secured from this investigation. 



PRAIRIE-DOGS. 



Measures for the destruction of prairie-dogs have been conducted 

 by field parties operating on Government lands and by cooperative 

 work with farmers and stockmen through the agricultural college 

 extension services in New Mexico, Arizona, Colorado, Utah, Wyo- 

 ming, Montana, and North Dakota. In all these States the cam- 

 paigns have been under cooperative agreements with the State exten- 

 sion services, and in New Mexico the State Council of Defense has 

 joined in the work and contributed funds to extend its scope. 

 Farmers and stockmen are taking the greatest interest in the work 

 as a direct method of saving crops and forage. 



As an illustration of the effectiveness and economy of the methods 

 of destroying these pests, a badly infested plot of 320 acres was 

 chosen for a demonstration in northern Arizona. One man spent a 

 day distributing poison over this area, at a total cost for labor and 

 material of $9.79. The following day 1,641 dead prairie-dogs were 

 picked up from this tract. With the number which must have died 

 in their holes, there can be little question that more than 2,000 prairie- 

 dogs were destroyed in this experiment. 



More than 3,500,000 acres of Government land have been prac- 

 tically freed from these pests. 



GROUND SQUIRRELS. 



Various species of ground squirrels extremely destructive to crops 

 occur in enormous numbers over a large part of many of the Western 

 States. The bureau has been engaged in a campaign for their con- 

 trol in cooperation with the State extension services in North Dakota, 

 Montana, Idaho, and Wyoming; and introductory demonstrations 

 leading toward similar campaigns have been made in several others 

 of the cereal-producing States. In California there is also being 

 conducted a campaign against these pests, with the State and county 

 commissioners of horticulture and some county farm advisers co- 

 operating. 



The poisoned grain used in the campaigns to destroy ground 

 squirrels on private lands is prepared under the supervision of field 



