Abstract
Of various factors responsible for the diet selection of frugivorous birds, accessibility to fruit is assumed to play a major role. Swida macrophylla and Trema orientalis are sympatric species in Yakushima Island, Kagoshima Prefecture, southern Japan. Although their fruiting periods overlap, their morphological fruiting patterns differ greatly. Therefore, we studied the effect of accessibility to fruit on the diet selection of frugivorous birds. We established fixed observation points in the study site and also took morphological measurements of the birds. Bird species attracted to the fruit differed greatly between the two tree species. Ficedula narcissina and Hypsipetes amaurotis mainly visited Swida macrophylla and employed hover-capturing to eat the fruits. Zosterops japonicus, on the other hand, primarily foraged on Trema orientalis by hopping. A comparison of bird morphological features and fruiting patterns suggests that birds select trees which facilitate their access to the fruit.
