Black bears (Ursus thibetanus) feed on the Fagaceae hard mast including beech and oaks in fall. Distribution of dominate Fagaceae tree species differs regionally and mast production shows annual fluctuations. However, there is little habitat-selection study which investigated relationship with spatial distribution of hard mast availability. We test hypothesis that bears selectively use the areas where hard mast are abundant.

Study areas were Toyama Prefecture (2005－2007) and Okutama mountains (2009－2010) where dominate tree species were different. We developed “energy reflecting maps” by converting production levels of each Fagaceae mast into energetic productivity (kcal/㎡). We analyzed bear’s selectivity for available energy using 12 bears with GPS collars.

Contrary to our hypothesis, bears not necessarily selected energy-abundant areas. This is because some bears used the Fagaceae species or vegetation types which have relatively lower available energy. However, the energy quantity might be sufficient to fill up bears’ demand. Rather, these individual variations in habitat selection might have role on decreasing competition for a limited resource among bears.