The Effect of Agricultural Clearing on the Breeding Success of the White-Tailed Black Cockatoo

Abstract

SAUNDERS, D. A. 1977. The effect of agricultural clearing on the breeding success of the White-tailed Black Cockatoo. Emu 77: 180–184. The ecology of the White-tailed Black Cockatoo has been studied in two main areas, Coomallo Creek and Manmanning. Coomallo Creek has large tracts of uncleared sandplain heath surrounding the woodland areas where the birds nest. Manmanning is cleared farmland with small discrete patches of uncleared land surrounding homesteads, along some roads and along parts of the railway line. The birds breeding at Manmanning produce fewer offspring per breeding unit than at Coomallo Creek, and Manmanning nestlings have a slower growth rate and lower fledging weight than Coomallo Creek nestlings. It is suggested that the different success is because at Manmanning food is patchily distributed and scarcer. The patchy distribution causes the birds to spend considerable time gathering food and commuting to and from their nests. In hot weather when foraging time is reduced the birds may not have enough time to satisfy their own requirements as well as those of their offspring. The provision of corridors of uncleared vegetation linking reserves would lead the birds from one source of food to the next and probably overcome the problem.