Comparative foraging ecology of five species of ground-pouncing birds in western Australian woodlands with comments on species decline

抄録

In this paper, we compare the foraging ecology of five Australian robins (Petroica multicolor, P. goodenovi, Eopsaltria griseogularis, Microeca fascinans, and Melanodryas cucullata) in woodlands of Western Australia. Australian robins are insectivorous and obtain the greatest proportion of their prey by pouncing from a perch to the ground. Data were collected at three different sites in eucalypt (Eucalyptus) woodland and two sites in acacia (Acacia) woodland. The species differed in habitat, structure of the ground substrates where prey were taken, proportion of foraging manoeuvres used, height of foraging perches and prey-attack distances, though there were broad overlaps in all foraging dimensions. Within a site, species were more similar to each other in their foraging behaviour and selection of foraging substrates than they were to conspecific individuals occurring elsewhere. This indicates that potential foraging behaviours were very broad, and their expression is determined by the characteristics of the habitat and available prey. At all sites, robins took prey from ground substrates characterised by a mosaic of bare soil, low ground vegetation, and litter. The smallest species, P. goodenovi, used lower perches than the other robins and probably searched for small prey which it located at short distances. P. goodenovi had the widest distribution and was the most abundant of the species studied. The implications of these findings for the conservation of ground-foraging birds in Australia are discussed.