Twenty-eight years of monitoring a breeding population of Carnaby's Cockatoo

Abstract

The breeding population of Carnaby's Cockatoo at Coomallo Creek in the northern kwongan (sandheath) of southwestern Australia was monitored from 1969 to 1996. The cockatoos breed in hollows in trees in a belt of woodland through the centre of the study area and feed in adjacent kwongan. During the period, the study area was progressively and rapidly cleared for broad-scale cereal and sheep farming. The area of native vegetation cover was reduced from 90% in 1959 to 25% in 1996. The number of breeding attempts fell over the period of the study from around 80 attempts in the early part of the study to less than 40 by 1996. The initial decline was due to a combination of loss of habitat and increased mortality of the birds due to the use of wing tags to mark them individually. The subsequent decline was most likely due to loss of habitat. The importance of the northern kwongan and associated woodland patches to the conservation of animals like Carnaby's Cockatoo that breed in tree hollows is discussed. Unless areas of woodland on private land and adjacent kwongan are afforded more protection, the future for hollow nesting species that feed on native vegetation like Carnaby's Cockatoo is bleak.