BUREAU OF BIOLOGICAL SURVEY. 333 



species until losses from them will become comparatively small. 

 The extermination of harmful rodents over vast areas is also only 

 a matter of continued operations. Two counties in Arizona and 

 four in Kansas have been completely freed from prairie dogs during 

 the year and the numbers of rodents are being decreased year by 

 year over a vast area. 



Work at the experimental fur farm and other investigations of fur 

 farming continue to 3neld information of the greatest practical value 

 to this new and rapidly growing industry. 



PREDATORY ANIMALS. 



Establishment by the bureau of definite organizations in the West- 

 ern States, upon which live-stock producers call for assistance in case 

 of serious depredations by wolves, coyotes, and other animals, and 

 through which definite information is available as a basis for care- 

 fully projected campaigns, is steadily reducing losses of live stock 

 from this source, which, at the time the organized work was under- 

 taken in 1915, were estimated at more than $20,000,000 annually. 

 These organizations, in the grazing States of the West and also in 

 Michigan, work in cooperation with State departments of agricul- 

 ture. State live-stock commissions, State game commissions, county 

 organizations, stockmen's associations, and individuals to clear pred- 

 atory animals from great units of Federal, State, and private lands 

 used for grazing. This is accomplished by means of carefully 

 planned trapping, shooting, and den-hunting operations and by poi- 

 soning campaigns, which have been conducted on an unprecedented 

 scale. 



Trained hunters have also been stationed along passes leading 

 across the Mexican border to capture promptly wolves and other 

 predatory animals as they enter this country, and arrangements have 

 been made with stockmen in northern Mexico for the maintenance 

 of hunters who work in cooperation with the Federal and State 

 forces of the United States along the international border. A con- 

 stantly recurring invasion of wolves from Mexico into New Mexico 

 and Arizona is being thus successfully controlled. Similar con- 

 certed action along adjacent State borders is very effective in de- 

 stroying wide-ranging animals like wolves. Cooperation with other 

 Federal agencies, as the Forest Service, of the Department of Agri- 

 culture, and the Office of Indian Affairs and the National Park Serv- 

 ice, of the Department of the Interior, has also been obtained in 

 this work. 



During the year an average force of 266 hunters, trappers, and 

 poisoners was employed under bureau supervision, and many thou- 

 sands of stockmen participated in the distribution of poisoned baits 

 during the organized drives. Part of the men employed were paid 

 by the Federal Government and part by the States and other co- 

 operating agencies, which contributed $196,405 to the work. Hunt- 

 ers are required to turn in as evidence the skins or scalps of animals 

 killed when found in condition for the purpose. Such positive evi- 

 dence was obtained during the year in the case of 30,986 predatory 

 animals, of which 687 were large gray wolves, 27,185 coyotes, 2,827 

 bobcats and Canada lynxes, 173 mountain lions, and 114 bears. Bears 

 are generally regarded as game animals and are protected by some 



