"Rodents, numerous and spreading over nearly 80 percent of the Boise watershed, have undoubtedly been responsible for no small part of the present erosion. Wholly dependent upon the herbaceous plants for their food supply, their tremendous numbers, along with over-grazing by livestock and unfavorable climate, have been an important contributing factor in depleting this cover, and thus have greatly reduced the protection afforded the soil and subjected it the more to increased sheet erosion. Even light rains on rodent-infested areas are likely to start cutting, which may develop into destructive gully erosion because of the almost immediate accumulation of run-offs in the myriads of burrows and channels which these animals construct just under the surface of the soil." The control of rodents is vital to the successful operation of reclamation projects in the western third of the United States. Rodents, particularly pocket gophers, find the banks of irrigation canals an ideal location for their burrows and runways. These subterranean passageways frequently are the cause of serious breaks in canals, through which the flow of irrigation water is diverted and wasted to flood adjacent lands, destroying valuable crops, and indirectly ruining others by causing delays in delivery of water. Through the E.C.W. program, C.C.C. crews working under the direction of experienced foremen trained by the Biological Survey have greatly reduced this menace. In the past year alone half a million acres of canal banks and contiguous lands were treated by C.C.C. rodent-control crews with a thoroughness that will be of lasting benefit to the nation's reclamation projects. Examples of Benefits Derived A few concrete examples will illustrate the great good that has resulted from the E.C.W. rodent-control program. A group of farmers living at Springfield, Idaho, suggested to the camp superintendent there that the jack rabbit control work done by the E.C.W. crew during the summer of 1935 might pay the cost of the camp. It is estimated that not less than 600,000 rabbits were killed by this crew on public lands adjacent to farming areas between American Falls and Moreland, Idaho. The work afforded protection to not less than half a million dollars worth of cultivated crops and to more than 75,000 acres of grazing lands. The control work carried on by an E.C.W. crew near Weber Lake, Calif., in 1933 has been responsible for a 50 percent comeback of the grass on a large mountain meadow, which had been made a dust heap because of pocket gopher workings. The pocket gophers had honeycombed the surface of the ground, and sheep had trampled out most of the grass, while livestock grazing had been reduced to a negligible figure. The restoration in two years was due primarily to the elimination of the pocket gophers.