FORAGING ECOLOGY OF SOME INSECTIVOROUS AND NECTARIVOROUS SPECIES OF BIRDS IN FORESTS AND WOODLANDS OF THE WET-DRY TROPICS OF AUSTRALIA

The foraging ecology of 40 species of insectivorous and nectarivorous birds was studied in the monsoon forests, woodlands and open forests of the Kakadu National Park, Northern Territory. Most used a broad range of foraging heights, sites and behaviours. The more specialised species were usually terrestrial or aerial feeders. When taking invertebrates, honeyeaters used a narrower range of foraging strategies than did obligate insectivores. The degree of potential overlap in foraging ecology between species pairs was not related to abundances or morphological similarities. Food-related morphological characters of a species were not strongly related to its foraging ecology. The generalised foraging mode of most species and the apparent lack of interspecific competition are probably attributable to the climatic variability found in this region.