How Long Fruit-Eating Birds Stay in the Plants Where They Feed: Implications for Seed Dispersal

Abstract

Theories relating foraging behavior of frugivorous birds to patterns of seed dispersal have not considered the effect of prolonged visits by birds to fruit-bearing plants. We present data showing that in New Guinea some obligate frugivores (fruit pigeons and bowerbirds) spend more time in fruit-bearing plants than is required for feeding. Often they remain in the plant between feeding bouts. On the other hand, some insectivorous fruit-eating birds (birds of paradise) visit fruit-bearing plants only long enough to feed. Longer visits by fruit pigeons and bowerbirds may result, in different cases, from greater commitment to frugivory, to predator and competitor avoidance strategies involving crypsis, and to less time-demanding breeding systems. Longer visits may result in a larger number of seeds being dropped beneath food trees.