Mammal Study

The relationship between the number of fecal pellet groups found in line transects and estimates of deer density based on block counts on Mt. Ohdaigahara in central Japan was examined and the validity of fecal pellet group counts for obtaining an index of sika deer population density was assessed. Sika deer population densities estimated by block count were 13.0/km² in spring, 18.3/km² in summer and 19.0/km² in autumn. Fecal pellet group counts showed low positive correlations with deer density in spring and autumn (0.69 in spring and 0.68 in autumn), but not in summer, indicating that deer density may not be predictable then. We suggest that fecal pellet group count reflects deer density in spring or autumn, and might be feasible as an index of deer population density.

We examined the home range and habitat use of three female brown bears (Ursus arctos) in the Urahoro region, eastern Hokkaido, Japan, where crop depredation by bears has increased since 1996. The average annual home range size calculated by the minimum convex polygon method was 43.04 ± 9.52 km² (mean ± SD, N = 5). Summer (June–September) home ranges were larger than spring (April–May) and fall (October–December) ranges. The home range of brown bears in the region was larger than those in other areas of Hokkaido, such as the Oshima and Shiretoko Peninsulas. This suggests that habitat quality and population density are lower in the Urahoro region than in other areas. One of two bears for which we examined habitat preferences depended on crop fields during the late summer, whereas the other bear remained in the forest throughout the year. Brown bears in this area preferred mixed forest and avoided deciduous broadleaf forest and conifer plantations.