Long-term persistence of the Australian Magpie, Gymnorhina tibicen, in Kings Park, Perth

Abstract

A survey of Australian Magpies, Gymnorhina tibicen, in Kings Park, Perth, Western Australia, in 1938 identified 84 individuals in nine groups. The survey was repeated 62 years later in 2000 and identified 98 magpies in 19 groups. The sex and age composition of the population during the two surveys was broadly similar, with 69% of the birds in 1938 classed as adult and 75% in 2000. In 1938, 31% of the population were adult males and 38% adult females compared with 40% and 35% respectively in 2000. Seven of the areas occupied by groups in 1938 were also occupied by one or more groups in 2000. The greater number of groups in 2000 is partly due to two or more groups occupying areas used by one in 1938. Also in 2000, several groups occupied parts of Kings Park where no magpies were recorded in 1938, but the territories of two groups in 1938 were unoccupied in 2000. In part, the increase in the number of magpies and groups since 1938 is the result of clearing large areas of bushland and replacing it with lawns and gardens, thereby creating more habitat for magpies. The remainder of the increase may be the result of more regular watering of lawns and gardens in the park, increasing the food resources available to magpies as water supplies improved. The areas not used in 2000 may have become too densely vegetated or affected by increased traffic on the main road along the park's northern boundary, which may restrict movements of magpies between the park and the lawns and parks of the adjoining residential area.