Foraging Ecology of Birds in an Upland Tropical Rainforest in North Queensland.

Abstract

Vertical distribution of herbivores, mixed feeders and insectivores in an upland tropical rainforest reflected variation of foods present in different strata. Arboreal insectivores utilized the widest range of strata because of a wider distribution of arthropod foods. Differential utilization of vertical strata was the most important factor to bring about niche differentiation, not only between the three feeding categories but between species within each of the categories. Species whose vertical ranges were similar were segregated by differential utilization of foraging sites, by foraging behaviours and/or by food resources. Seasonal migration, variation in diet and shifts in vertical foraging levels, and/or diurnal variation of foraging times, resulted in a finer partitioning of resources between those species whose niches greatly overlapped.