Habitat selection at multiple spatial scales by foraging Glossy Black-cockatoos

Abstract

Habitat selection among vertebrates entails decision making at a number of spatial scales. An understanding of factors influencing decisions at each of these scales is required for the effective management of wildlife populations. This study investigates the foraging ecology of a population of Glossy Black-cockatoos in central New South Wales. We took advantage of the characteristic feeding sign produced by Glossy Black-cockatoos to examine factors influencing habitat selection at multiple spatial scales. Birds preferred to forage at sites where food was abundant and avoided open sites where the predation risk may be greater. Their two food species, 'Allocasuarina diminuta' and 'Allocasuarina gymnanthera', differed in profitability (kernel intake rate as measured by the ratio of seed weight to total seed and cone weight), as did trees within a species. Both species were utilized extensively, although foraging intensity was greater at sites where the more profitable species was present. In order to maximize their food intake, birds selected individual trees on the basis of cone abundance and profitability. Cones produced in the previous year were preferred.