Abstract

Reproduction and demography of the northern quoll, Dasyurus hallucatus, was assessed using live-trapping and radio-tracking at a lowland savanna site in Kakadu National Park between 1992 and 1995. Northern quolls were found to exhibit a highly synchronous breeding cycle with mating occurring late May/early June. The greatest peak in apparent male abundance was during the mating season, but this was probably due to their increased mobility at this time. Males demonstrated complete post-mating mortality, with most males dying within two weeks of mating. Young were born in mid to late June with the mean initial litter size for 8-teated females being 7.3. First-year mothers were more likely to have predominantly male litters, whereas second-year mothers had more females. The survival rate of pouch young was high but, once young were left in the den, survival was poor. Peaks in abundance for both sexes occurred when the juveniles first entered the trappable population in November each year. Mortality of females was high, with only 27% of females surviving to wean a second litter, and none bore a third. The most common proximate cause of adult mortality was predation. Increased predation pressure on adults, in particular due to a reduction in shelter and ground cover from too-frequent fire may make northern quolls vulnerable to local extinction in lowland savanna.