The distribution and abundance of the burrowing bettong (Marsupialia : Macropoidea)

The burrowing buttong (Bettongia lesueur) has been extinct on mainland Australia since the early 1960s, but was believed to persist on four islands off the coast of Western Australia-Bernier, Dorre, Barrow and Boodie. We surveyed these islands in 1988-89 to ascertain the status of bettongs and other endangered mammals. Bettongs were widespread and comparatively abundant on three islands but absent from the fourth. Bettongs occurred at estimated densities of c. 14-17km-2 on Bernier, Dorre and Barrow Islands, suggesting approximate minimum populations of 650, 1000 and 3400 respectively and a total minimum population for the species of c. 5000 individuals. It would appear that a poisoning campaign in 1985 to eliminate Rattus rattus from Boodie Island also eliminated the bettong. The burrowing bettong has apparently been absent from a fifth island and its type locality, Dirk Hartog Island in Shark Bay, since early this century. The vulnerability of this species is highlighted by its extinction on mainland Australia and by the loss of two of its five island populations. It now occupies less than 0.01% of its historical range. Its status as rare and endangered is justified.