Spatial Responses of Field (Microtus Agrestis) and Bank (Clethrionomys Glareolus) Voles to Weasel (Mustela Nivalis) Odour in Natural Habitat

Abstract

The odors of predatory mammals, i.e. mustelids, might be recognised by potential prey, i.e., small rodents, as a signal of predation risk. Using the sense of smell, rodents could detect the presence of predators and respond accordingly by avoiding areas where they have encountered the predator’s scent (Jędrzejewski et al., 1993). Early recognition of predation risk by detection of predator odors might thus increase the chances for survival for small rodents (Borowski, unpublished data). For example, experiments in both laboratory and field conditions demonstrated that exposure to weasel odors caused voles to exhibit antipredatory reactions (Jędrzejewski et al., 1993). Voles that are in danger of predation by mustelids apparently reduce the risk of predation by moving to a microhabitat that lacks evidence of predators (Korpimäki et al., 1996). Voles under predation risk might also limit or change their feeding preferences (Sullivan et al., 1988; Borowski, 1998a) and reduce their locomotor activity to a smaller home range area (Gorman, 1984; Jędrzejewski et al., 1993; Borowski, 1998b). Seasonal differences in responses to weasel odors in field populations of root voles (Microtus oeconomus) have been demonstrated: during the breeding season, voles avoided the weasel odour to a greater extent than during the non-breeding season (Borowski, 1998b).