The impact of predation on burrow use by Arctic ground squirrels in the boreal forest

In sedentary animals, the choice of a suitable home site is critical to sur vival and reproductive fitness. However, habitat suitability may vary with predation risk. We compared habitat use of Arctic ground squirrels (Spermop hilus parryii plesius) living in the boreal forest under conditions of fluc tuating predation pressure. In our study area, predators show ten-year cycl es in numbers that track that of their primary prey, the snowshoe hare (Lep us americanus). In 1993, we compared burrows that continued to be occupied following the period of intense predation during the hare decline of 1990-1 992 with those that became vacant, and with random locations. We contrasted these sites to those in a predator exclosure where predation pressure was minimized. Burrows on control sites were located on sloped sites with high visibility. Burrows that remained occupied during the period of intense pre dation were more likely to be in open areas with fewer fallen trees than bu rrows that became vacant. We used discriminant functions derived from the c ontrol sites and found that 89% of the burrows on the predator exclosure we re classified as being similar to the random locations on control sites. We conclude that the distribution of Arctic ground squirrels in the boreal fo rest is a direct function of predator presence.