2009 年 9 巻 2 号 p. 13-17
In two fragmented small woods we assessed the overall distance traveled and the distances moved from the nest to nocturnal sites outside the nest by Pteromys volans orii. Records of the distances traveled per 30min showed that the Siberian flying squirrel moved significantly longer distances in the "after sun-set" period than in the "late night" period. Relatively short distance travelled in the "before sunrise" period suggested that the squirrel sometimes remained in one tree and foraged actively there during this period. Between the nest and nocturnal locations, males moved significantly greater distances than females in spring-autumn and winter. In both sexes, the distance traveled in winter was greater than that in spring-autumn, but the difference was not significant in females. Males moved longer distances to maintain their home ranges, which incorporated the home ranges of several females. Food resources were limited to a few tree species, and nests were limited to just a few cavities and dreys that provided good protection against low temperatures in winter. We suggest that the Siberian flying squirrel moves longer distances in winter because of the low numbers of food trees and winterproof nests. Females might gravitate all year towards nests that are more suitable for breeding and close to food resources; this may explain why the difference between the two seasons in the distances moved by females was obscure.