The Cattle Egret, Ardeola-Ibis, in Southeast Queensland

Abstract

Annual counts made by the Queensland Ornithological Society (1972-83) were used to monitor cattle egret numbers in south-east Queensland. Numbers in coastal areas were reasonably stable during this period but, after an initial stage of low numbers, the inland population increased rapidly from 1975 to 1981. An exponential equation, N=0.752 exp(0.320t), gave the best fit to these data. Declines in numbers in 1977 might have been associated with low rainfall in the Moreton meteorological region. At the start of the survey the cattle egret was the most abundant ardeid in coastal areas and, as its numbers increased in inland areas, there was a coincidental decline in numbers of great egret Egretta alba.