Some Population characteristics of Perameles gunnii in Victoria

Abstract

On the Australian mainland, the eastern barred bandicoot is now restricted to the city of Hamilton in western Victoria. Mark-recapture data from four main population areas, used in a Petersen index, gave a population estimate of about 134 individuals in 1988. When areas not sampled for population abundance were included, the total estimate of abundance for Hamilton was 246 individuals. Sex ratio was significantly male-biased for adults (68%), whereas the sex ratio for pouch young was about equal (45% male). The subadult age class constituted 8.2% of the captures, and accounted for only 10% of the total number of pouch young produced. Mean litter size was 2.11. The number of lactating females and the litter size were greatest during early spring. Eighty per cent of the offspring were produced in litters of 2 or 3. Nests were observed in various substrates, including man-made structures. Selected foraging areas had few native grasses, high ground cover, tall plant height and acid soils of low to medium compaction. Bandicoots were observed feeding on invertebrates, with some orchard fruits also being eaten. Foraging patches were actively defended. Adult home ranges of males (mean 12.94 ha) were larger than those of females (mean 2.38 ha). No female moved more than 150 m whereas males moved up to 2.3 km from their initial point of capture. The major cause of adult mortality observed was road kills. Life-expectancy is probably less than 2 years. Juvenile mortality was high.