Beaver Census Methods in the Rocky Mountain Region

This paper is an evaluation of numerous beaver-census techniques as they apply to the Rocky Mountain region. In designing plans for management of the beaver (Castor canadensis), primary consideration must be given to enumeration and appraisal of extensive populations. Reports on surveys of this nature (Atwater, 1940; Tappe, 1942; Bradt, 1947; Swank and Glover, 1948; Fuller, 1953; and Knudsen, 1951, 1954), varying widely in approach and results, have been relatively frequent. In these studies, the census techniques mentioned have dealt almost exclusively with the use of lodges, dams, slides, food caches, and scent mounds as indices of beaver numbers. Verification of the accuracy of such population measurements was a necessary requisite for sound management plans in mountain terrain.