Foraging Behavior of Glossy Black-Cockatoos

The foraging behaviour of glossy black-cockatoos (Calyptorhynchus lathami) was studied in eucalypt forests near Eden, New South Wales, Australia, from June 1982 to February 1983. In this area, the cockatoos fed solely on Allocasuarina littoralis seeds that they extracted from closed cones, leaving characteristic feeding litter beneath favoured trees. The cockatoos bred in winter and apparently raised their young entirely on A. littoralis seeds. They spent 88% of the day foraging. The basis on which the cockatoos selected particular A. littoralis trees in which to forage was investigated. They chose trees with larger cone crops but showed no evidence of selecting trees on the basis of cone size. They concentrated their foraging in trees bearing cones with a high ratio of total seed weight to cone weight, which is an index of the potential return (i.e. seeds) from each cone-opening effort.