Birds as dispersers of Mallotus japonicus in a coniferous plantation.

Abstract

We observed the foraging behavior of frugivorous birds feeding on the seeds of Japan 2005 of a common pioneer tree, Mallotus japonicus, in a warm-temperate coniferous plantation in order to study the feature of seed dispersal. Twenty frugivorous bird species were observed in the plantation, among which, nine (Oriental Turtle Dove Streptopelia orientalis, Japanese Pygmy Woodpecker Dendrocopos kizuki, Daurian Redstart Phoenicurus auroreus, Narcissus Flycatcher Ficedula narcissina, Blue-and-white Flycatcher Cyanoptila cyanomelana, Siberian Flycatcher Muscicapa sibirica, Grey-streaked Flycatcher M. griseisticta, Varied Tit Parus varius and Japanese White-eye Zosterops japonicus) fed on seeds of M. japonicus. The turtle dove was not considered to be a seed disperser because it digests the seeds. It was estimated that 75% of dispersed seeds were eaten by the four flycatcher species. We concluded that these four species of Muscicapidae were effective seed dispersers of M. japonicus because of their high frequency of seed foraging.