RESPONSES OF SMALL MAMMALS TO RED FOX (VULPES-VULPES) ODOR

This paper describes the responses of 3 spp. of rodents (Apodemus sylvaticus, Microtus agrestis and Clethrionomys glareolus) and a shrew (Sorex araneus) to traps tainted with the fecal odor of a predator, the red fox. The rodents generally avoided traps bearing fox odor, but readily entered traps marked with rodent odor; shrews entered all traps equally. Among the rodents, avoidance of fox odor was strongest in male A. sylvaticus and C. glareolus and least in M. agrestis and female A. sylvaticus. Fox droppings were found principally along paths and in open habitats where, of the rodents mentioned, they were most likely to be encountered by A. sylvaticus. Avoidance of fox fecal and urinary odor in this species, especially by the active males, would reduce the time spent in areas frequented by foxes, and hence reduce the change of encountering the predator itself. M. agrestis would seldom encounter fox droppings in its subsurface runways, so avoidance of fox fecal odor would do little to reduce its chance of encountering the predator. Avoidance by the rodents of the fecal odor of badger, a predator not present in the study area, was only slightly less marked than their avoidance of fox fecal odor. Similar chemicals eliciting avoidance in rodents may commonly occur in the feces and urine of carnivores.