BUREAU OF BIOLOGICAL SURVEY. 429 



nent riddance of these destructive animals, and other counties are 

 profiting by this experience. The lack of sufficient Federal funds 

 to poison all Federal lands bordering on treated private holdings is 

 seriously impeding the progress of the cooperative campaigns and 

 this is becoming an increasing source of appeal on the part of land- 

 owners who have cleared their holdings and feel that they should be 

 protected from reinfestation from public lands. 



POCKET GOPHEKS. 



Recognition of the damage wrought by pocket gophers in orchards 

 and vineyards and in alfalfa and truck crop fields has brought about 

 an increasing demand for operations against them. Successful 

 completion of campaigns against the prairie dogs and ground 

 squirrels in many counties has served as a stimulus to under- 

 take the more difficult task of destroying pocket gophers. As these 

 are burrowing animals, the damage to plants occurs chiefly under- 

 ground and is often irreparable before the cause is noted. Knowl- 

 edge of the actual damage being done by these animals and demon- 

 stration that it can be effectively controlled at a reasonable cost 

 has led to extensive field operations against them during the year. 

 Such operations have proved that these pests can be successfully 

 eradicated through the use of various vegetable, grain, alfalfa, or 

 clover baits treated with strychnine and properly placed in the run- 

 ways, and by the use of traps of special design. 



Work against pocket gophers has been undertaken on a consid- 

 erable scale in Arizona, Colorado, Idaho, Kansas, Nebraska, New 

 Mexico, Oregon, Texas, Utah, and Washington, and considerable 

 demonstration work has been done in a number of other States. In 

 Arizona notable progress has been made in eliminating pocket 

 gophers from the citrus and date orchards, with the result that very 

 few trees have been killed by these animals during the past year in 

 such localities. Practically all orchardists in the citrus belt coop- 

 erated in treating their holdings with poisoned sweet potato baits. 

 One orchardist who had lost over $10,000 worth of trees from 

 pocket-gopher damage suffered no losses whatever this year, a result 

 of the effective work done. In California it was found that the 

 pocket gopher had gradually worked its way entirely around to the 

 northern end of the Salton Sea and had made its appearance in the 

 Coachella Valley. This presented a serious danger to the Govern- 

 ment date gardens established there. As the pocket-gopher injury to 

 a date palm is well concealed until the tree is permanently injured, 

 it appeared advisable that work be done at once to check the infesta- 

 tion, and steps were taken to that end. 



In the mountain parks and pasture ranges throughout the Rocky 

 Mountain region pocket gophers are doing an extensive injury to 

 grazing and hay meadows. The introduction of the promising head- 

 lettuce industry into the mountain valleys of Colorado has made the 

 work of controlling pocket gophers of far greater importance than 

 formerly, and they are now looked upon there as one of the greatest 

 pests. 



In seven of the important alfalfa-producing counties of Kansas 

 extensive operations against pocket gophers have been conducted. 

 A test was made on 57,400 acres, and the results proved so satisfac- 



