Predator Odors and Their Potential Role in Managing Pest Rodents and Rabbits

The snowshoe hare (Lepus americanus). several species of voles (Microtus spp.), the northern pocket gopher (Thomomys talpoidest. and the red squirrel (Tamiasciurus hudsonicus) cause serious damage to forest plantations and stands (and voles and pocket gophers in tree fruit orchards) by their feeding activities. Certain synthetic predator odors are reviewed which have produced significant avoidance responses in these pest species and reduced damage to crop trees on an experimental basis. In addition, the specific study reported in this paper was designed to assess the influence of predator odors on population density and survival of montane vole (M. montanus) populations in natural grassland habitat. Vole populations declined significantly in three consecutive winters on an area (and also on a replicated area in the third winter) treated with predator odors. These declines were caused by significantly lower survival in the treatment than control populations. Concurrent feeding damage to young apple trees was significantly reduced on the treatment area. We suggest that the predator odors may have attracted additional predators to the study area thereby increasing predation, as well as perhaps inducing behavioral-physiological stress in the vole populations. This technique could be implemented in forest plantations and tree fruit orchards as a means to disrupt resident vole populations and protect crop trees from damage. Proc. Vertebr. Pest Conf. (A.C. Crabb and R.E. Marsh, Eds.), Printed at Univ. of Calif., Davis. 13:145-150, 1988