Effects of red fox urine on foraging behavior in forest and residential populations of nocturnal rodents.

Abstract

Rodents perceive odors exuded by mammalian predators, and may alter foraging behaviors based on such information. The literature is mixed, however, and the extent to which wild rodents actually rely on olfaction to assess predation risk is not known. Aversion to predator scents may be innate or learned, and few studies have considered the potential importance of previous experience in determining rodent reactions to scent cues. We measured the effects of red fox (Vulpes vulpes) urine on the foraging activity of nocturnal rodents at track plates baited with sunflower seeds. To test the influence of previous experience, we set track plates both in areas close to human habitation (where rodents are presumably "predator naïve"), and in forest habitats where active predation by mammalian carnivores is likely. In both areas, a urine treatment and a scentless control were alternated in nightly trials. We discovered a significant difference between forest and residential populations of rodents in their response to red fox urine, though urine treatments did not differ from control treatments within either area. The difference in response to urine treatments was opposite of expected, with residential rodents significantly less active at urine‐treated track plates than forest rodents.