Australian remote Aboriginal communities commonly have large, free-roaming dog populations and relatively small cat populations. However, cats are becoming increasingly popular pets in these communities and it is essential to determine their potential impacts on wildlife to inform animal management practices. In a small island community, this study provided baseline population demographics and investigated dog and cat roaming behaviours and interspecific interactions. The dog population, estimated at 343 dogs, showed active periods at dawn and dusk. The cat population had doubled in 6 months to approximately 83 cats. Cats were observed roaming mainly from dawn until dusk, possibly avoiding periods when dogs were most active. The majority of cats were observed nonroaming. Three cats, however, were captured roaming during the night when all flightless wildlife were observed on our camera traps, suggesting potential impact on local wildlife through their hunting activities. These baseline data provide evidence on which to base management programs that include cats and their impacts on native wildlife. Further research using the multiple methods piloted in this study are warranted to monitor dog and cat populations and their interactions in this island community.

Between 2000 and 2002 two populations of the spotted-tailed quoll (Dasyurus maculatus) were studied on the New England Tablelands using trapping surveys and radio-tracking. Overall, 85 individuals were trapped, but only two individuals were trapped throughout the 26 months of the study. Trapping was male-biased (74%). Adult males (>1 year) were substantially larger than females. On average, males travelled longer distances than females, and the maximum distances recorded were 8.1 and 3.9 km for a male and female respectively. Home ranges of males overlapped substantially, whereas those of females appeared to be exclusive. Mortality rates and the turnover in the quoll populations appeared to be substantial and at the beginning of autumn the populations comprised ~50% juveniles.

Daily torpor and hibernation in adult mammals and birds have been extensively studied, but there is still much to learn about these fascinating physiological states. Because torpor in marsupials is widespread, partially because many marsupial species are small in size and heterothermy is common in small species, a growing number of studies have successfully investigated the use of heterothermy in this group.

However, most available data on heterothermy in marsupials exist for adults, and very little for growing young, mostly due to the challenges of measuring body temperature (T_b) in very small animals. There is currently much well-placed interest in the relationship between heterothermy and climate change, and how increasing air temperatures (T_as) may influence the use of heterothermy in these species. However, an animal may be most at risk of being negatively affected by increasing or variable T_as when it is still developing, especially in the case of marsupials which have potentially vulnerable altricial young. While some studies have investigated the development of thermoregulation in these tiny animals, continuous temperature measurements, that do not disturb the animal, have not been obtained due to the lack of appropriate technology.

The species chosen for my study were fat-tailed dunnarts (Sminthopsis crassicaudata) and stripefaced dunnarts (S. macroura), which are small marsupials from the family Dasyuridae (carnivorous marsupials). These two species are common in the wild and are ideal for laboratory work as they are easy to maintain and breed in captivity. The central theme of my study was the development of thermoregulation and torpor in very small, developing dunnarts. My first aim was to find a method of taking continuous measurements of T_b in very small animals that would not interrupt torpor use, as conventional transmitters are too large to be used in such small animals. By testing and confirming the reliability and accuracy of small temperature-sensitive transponders, I was able to use these to obtain continuous T_b readings in animals only 60 days (d) old, at approximately 8 g, and still in the nest.

The second aim of my study was to measure the development of endothermy and torpor use in the fat-tailed dunnart (S. crassicaudata). When animals were placed at T_a of 18 °C at 40 d they were poikilothermic, rapidly cooling to T_a, at 48 d animals cooled more slowly and could maintain T_b at approximately 25 °C, and at 56 d animals were endothermic, maintaining a high, normothermic T_b at the low T_a. Animals at ~60 d entered an apparent state of torpor, but being unable to rewarm, became hypothermic. However, these animals could rewarm when given access to radiant heat. Basking in this instance was not an optional method of reducing the cost of rewarming, but was instead necessary to rewarm and avoid hypothermia, and therefore essential to be able to use torpor. The incidence of hypothermia decreased until ~120 d when all animals could actively rewarm, without the aid of radiant heat. This is the first time, to my knowledge, that torpor use in an animal that is not yet fully endothermic has been observed, and indicates that the development of thermoregulation in this, and likely other species occurs in three stages: poikilothermy, partial endothermy and heterothermic endothermy. This discovery may also have some evolutionary implications that need to be considered, as heterothermy was possibly an intermediate stage between poikilothermy and homeothermy in the evolution of endothermy in mammals. The observation of basking in juveniles could reveal the step that explains how pre-endothermic animals were able to move beyond the heterothermic stage in the evolution of endothermy.

In eastern Australia, the spotted-tailed quoll (Dasyurus maculatus) is the species thought to be most likely at risk from aerial baiting with compound 1080 to control wild dogs (Canis lupus familiaris and C. l. dingo). Although it is known that quolls occasionally die of 1080 poisoning, the broader impact on populations remains unresolved. We therefore assessed the impact of a regular aerial baiting campaign on a population of spotted-tailed quolls. Baiting with 1080 meat baits was conducted by the local Wild Dog Control Association and followed the same procedure as in previous years with the exception that the biomarker, rhodamine B, was added to the baits. Prior to the baiting, 36 quolls were trapped and fitted with mortality radio-collars; 31 of these collars were still functional at the time of baiting. Quolls were monitored from a helicopter and on the ground until retrapped 5–9 weeks after baiting. Transmitters were then removed and a sample of vibrissae was taken for rhodamine B analysis. Carcasses found were analysed for 1080. Predator numbers were assessed before and after baiting using track pads across trails. Among the initial 36 radio-collared quolls, nine mortalities were recorded during the course of the study (seven after baiting). Only one of the nine deaths could be directly attributed to 1080 poisoning. In addition, vibrissae from five of the 35 individuals sampled after baiting were marked with rhodamine B, indicating that these individuals had consumed bait, and survived. Consequently, mortality attributable to this particular aerial baiting campaign was low, apparently because few quolls ate bait and most of those that did survived. Track counts for predators indicated a significant decrease in dog and fox numbers after baiting. Cat activity remained unchanged and the number of quoll tracks increased.

To further investigate the non-target impact of baiting using sodium monofluoroacetate (compound 1080) to control wild dogs, a population of radio-collarared spotted-tailed quolls was subject to an experimental aerial baiting exercise. The trial was conducted at a site on the New England Tablelands, New South Wales, without a recent history of that practice. Sixteen quolls were trapped and radio-collared before baiting. Fresh meat baits were delivered from a helicopter at a rate of 10-40 baits km⁻¹. In addition to 1080 (4.2mg), each bait contained the bait marker rhodamine B (50mg), which becomes incorporated into growing hair if an animal survives bait consumption. Two quoll mortalities were recorded following aerial baiting. Both quolls died 3-5 weeks after baiting when baits, on average, retained little 1080. None of the carcasses contained traces of 1080, but the test result is less reliable for the quoll that was found 19 days after its death although tissue was well preserved because of the cool weather. Nevertheless, given that this animal died 34 days after bait delivery, it appears likely that none of the raido-collared quolls succumbed to baiting. In contrast, vibrissae samples collected from 19 quolls captured after the baiting showed that 68% had eaten baits and survived. Furthermore, multiple bait takes were common, with up to six baits consumed by one female. The results demonstrate that most, if not all, quolls survived the baiting trial, including those that consumed dog baits. Hence bait consumption figures 'per se' are not indicative of mortality rates attributable to poisoning.

In Australia, baiting with 1080 (sodium fluoroacetate) is widely used to reduce predation of native wildlife by the red fox. However, such control programs may place some native carnivores at risk, particularly the spotted-tailed quoll in eastern Australia. We measured the mortality in a total of 57 quolls fitted with mortality radio-transmitters during four experimental fox baitings with Foxoff® 1080 baits containing Rhodamine B in north-east New South Wales. In all experiments quolls visited bait stations regularly and removed a total of 20 baits. All but one of these baits was found in the vicinity of the bait station, indicating that quolls did not ingest baits. This was confirmed by the absence of Rhodamine B in the vibrissae of all quolls retrapped after baiting. The only quoll that may have died from a bait had eaten a cached bait some six weeks after baiting concluded. Thus, baiting did not threaten any of the quoll populations sampled. Therefore it appears that most restrictions imposed to protect spotted-tailed quolls during fox baiting are unnecessary as long as this bait type is used.