Tree species preferences of insectivorous birds in a Japanese deciduous forest: the effect of different foraging techniques and seasonal change of food resources

Abstract

I examined the effects of arthropod abundance and of bird foraging tech- niques on the tree species preferences of seven insectivorous bird species in a temper- ate deciduous forest. It is hypothesized that bird species with a wide range of foraging techniques respond more flexibly to the spatial distribution and seasonal change of prey than those with specialized foraging techniques. This hypothesis was supported by the fact that tits, bird species with a wide range of foraging techniques, changed their techniques when foraging in tree species with different foliage structures. They also used various tree species in late summer when food requirements increased owing to the addition of nestlings and fledglings. Bird species with a narrow range of foraging techniques, such as flycatchers and white-eyes, did not change their tech- niques among tree species and had strong tree species preferences in all research peri- ods.