2003 年 7 巻 1 号 p. 113-122
An altitudinal survey of correspondences between fruiting phenology of fleshy-fruited tree species and seasonal dynamics of frugivorous birds was carried out for 50 weeks across three vegetation types on Mt. Kinabalu, Borneo: a hill forest (800 m a.s.l.), a lower montane forest (1,700 m a.s.l.) and a subalpine forest (3,100 m a.s.l.). In the hill forest, a large fruiting peak following the general flowering period was observed during October–November in 1996 and a marked fruitless period was observed during February–April in 1997. During the fruitless period, the number of resident frugivorous birds decreased in some families. In the lower montane forest, a bimodal fruiting pattern was observed. A large number of frugivorous temperate migrants occurred and removed a lot of the fruit when the fruiting peak occurred. The number of resident frugivorous birds increased and several lowland bird species were observed when the number of resident birds decreased in the hill forest. In the subalpine forest, more continuous and irregular fruiting patterns without outstanding peaks were observed and the number of resident frugivorous birds was more stable throughout the year. These suggested (1) temperate migrants visited mainly the lower montane forest to obtain fruit resources and (2) altitudinal movements of lowland bird species to montane vegetation might occur seasonally, revealing that seasonal movements and migrations to track fruit resources might be common among frugivorous birds occurring on Mt. Kinabalu.
