The number of common wombats can be estimated directly either by capturing every animal during a single trapping session or by mark-recapture over at least three trapping sessions. Indirect estimates can be obtained by recording the number of burrows used every 24 h. Spotlight counts do not provide accurate population estimates.

Eutherian carnivores tested were more sensitive to 1080 poison than marsupial carnivores. Both groups of animals displayed similar symptoms but there was wide intra- and interspecific variation in the time to onset, the sequence of occurrence and duration of the symptoms. The risks that individual carnivores face from primary and secondary poisoning have been assessed. Theoretically, dingoes probably face the greatest risk amongst the species studied, followed by members of the smaller dasyurids and feral cats. Members of the larger dasyurids and long-nosed bandicoots probably face the least risk. Factors likely to influence the actual effect of 1080-poisoning campaigns on carnivore populations are discussed.

The Wet Tropics bioregion of north Queensland has been identified as an area of global significance. The worldheritage-listed rainforests have been invaded by feral pigs (Sus scrofa) that are perceived to cause substantial environmental damage. A community perception exists of an annual altitudinal migration of the feral-pig population. The present study describes the movements of 29 feral pigs in relation to altitudinal migration (highland, transitional and lowland areas). Feral pigs were sedentary and stayed within their home range throughout a 4-year study period. No altitudinal migration was detected; pigs moved no more than a mean distance of 1.0 km from the centre of their calculated home ranges. There was no significant difference between the mean (AE95% confidence interval) aggregate home ranges for males (8.7 AE 4.3 km 2 , n = 15) and females (7.2 AE 1.8 km 2 , n = 14). No difference in home range was detected among the three altitudinal areas: 7.2 AE 2.4 km 2 for highland, 6.2 AE 3.9 km 2 for transitional and 9.9 AE 5.3 km 2 for lowland areas. The aggregate mean home range for all pigs in the present study was 8.0 AE 2.4 km 2 . The study also assessed the influence seasons had on the home range of eight feral pigs on the rainforest boundary; home ranges did not significantly vary in size between the tropical wet and dry seasons, although the mean home range in the dry season (7.7 AE 6.9 km 2 ) was more than twice the home range in the wet season (2.9 AE 0.8 km 2 ). Heavier pigs tended to have larger home ranges. The results of the present study suggest that feral pigs are sedentary throughout the year so broad-scale control techniques need to be applied over sufficient areas to encompass individual home ranges. Control strategies need a coordinated approach if a long-term reduction in the pig population is to be achieved. * potential migration of pigs between lowland and highland habitat areas in response to seasonal influences, and * seasonal home-range patterns.

The sensitivity of a species to 1080 poison is difficult to predict from toxicity data for other, closely related species. LD*50s of practical use for evaluating the risk species might face from 1080-poisoning campaigns can be obtained for untested members of some groups by the use of either values for similar species, regression equations involving body weight, or the lower 95% confidence limits of the distribution of LD*50S of members in each group. Among the 171 species for which there are data there was considerable variability in the time until signs of poisoning became apparent (0.1 h- >7 days), the time to death (0.1 h- >21 days) and the time until animals began to show signs of recovery (2 h-18 days). Marsupial carnivores generally showed signs earlier and died or recovered quicker than eutherian carnivores, eutherian herbivores and the marsupial herbivores of eastern Australia, even though the last three groups have lower LD*5OS. Reptiles and amphibians generally were the slowest to show signs of poisoning, to die or to recover, and had the highest LD50s . All species in Australia for which toxicity data are available were ranked according to the percentage of their body weight they would have to eat of various poison baits to receive an LD*5O. Many non-target species require lower percentages than the target animals but the actual consumption of lethal bait may be affected by various factors. Finally, an evaluation is given of the major groups of animals potentially most at risk in 1080-poisoning campaigns in Australia, based on their susceptibility to 1080.

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