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The intrusion of Asiatic black bears (Ursus thibetanus) into human-populated areas has become a major wildlife issue in Japan. In 2004 and 2006, numerous bears appeared in populated areas, causing an increase in the number of human-bear accidents and culled bears. Several ideas have been advanced to explain the intrusions: over the long term, the decline of the hunter population has made bears less aware of humans, abandonment of rural mountains (satoyama) provides good habitat for bears near human areas, and unharvested crops and fruit and vegetable waste attract bears to human areas (Oi and Yamazaki 2006). However, these reasons do not explain the yearly fluctuation in human-bear conflicts. Shorter term triggers for the intrusions have also been advanced: lack of food resources due to annual variations in food resource availability and fluctuations in bear populations (Oi and Yamazaki 2006). In fact, hard mast abundance and human-bear conflicts are correlated (Taniguchi and Osaki 2003; Oka et al. 2004). Hard mast is the main autumn food for bears (eg, Hashimoto and Takatsuki 1997), and bears have been reported to change the kind of hard mast they use according to abundance (Mizoguchi et al. 1996; Hashimoto et al. 2003). In the northern Japan Alps, bears descend from their summer habitat, where green vegetation is available, to autumn habitat, where hard mast is available (Izumiyama and Shiraishi 2004). However, how hard mast directly affects bear foraging behavior is not known. In terms of summer food resources, Koike et al.(2008) reported that Prunus jamasakura fruit matures later at higher altitudes, and …