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The acceptability of three types of non-toxic predator baits to a variety of indigenous non-target species was determined in the laboratory. The bait-types tested were: Dried Meat Bait (DMB), Probait and two sizes of FoxOffTM baits (30 g and 60 g). The potential poisoning risk, if the baits had been toxic, was calculated for each species from their consumption of non-toxic bait and their sensitivity to 1080. Three species consistently sampled baits; Dasyurus geoffroii, Trichosurus vulpecula and Rattus fuscipes. Where species have had exposure to fluoroacetate-bearing vegetation, their consumption of bait and their level of tolerance to 1080 was such that only 2 of 15, 4 of 15, and 3 of 6 species were considered to be potentially at some risk from toxic DMBs, Probait, and FoxOffTM baits, respectively. In contrast, and mainly because of their lower tolerance to 1080, the theoretical risk for those species without evolutionary exposure to fluoroacetate-bearing vegetation was such that 6 of 12, 8 of 12, and 8 of 9 species theoretically face a high or moderate risk from 3-mg DMBs, Probait, and FoxOffTM baits, respectively. We emphasise, however, that theoretical risk does not necessarily equate to a practical risk, and these results are best used to determine which non-target species should be monitored at the population level during predator-control operations. Factors affecting the potential risk to non-target indigenous animals, and some cautions when extrapolating data from laboratory-based studies to the field situation, are discussed.

The sensitivity to fluoroacetate (1080) of a number of species of rodents and dasyurids with and without evolutionary exposure to fluoroacetate-bearing vegetation was determined. Rattus fuscipes, and species of Pseudomys from populations with exposure to this vegetation, were particularly tolerant to fluoroacetate. However, the level of tolerance varied among the different populations of each species, depending on the degree to which the toxic plants were present in their microhabitat. The tolerance of the F1 offspring of sensitive R. fuscipes (South Australia) crossed with tolerant conspecifics from Western Australia was mid-range between those of the parental populations. The sensitivity of introduced R. rattus and Mus domesticus from areas with fluoroacetate-producing plants in Western Australia was similar to that reported elsewhere for these rodents. This suggests that their relatively short coexistence with the toxic plants has had little obvious impact on their level of sensitivity to fluoroacetate. The dibbler, Parantechinus apicalis, which coexists with the toxic vegetation, was exceptionally tolerant for a native carnivore/insectivore (LD50 ~35 mg 1080 kg–1). In contrast, however, Phascogale tapoatafa from southern Western Australia was more sensitive to 1080 than was expected, with an estimated LD50 of 7 mg 1080 kg–1. Although the level of tolerance to fluoroacetate was seen to vary depending on the level of exposure of each species/population to fluoroacetate-bearing vegetation, our findings provide further evidence of the evolutionary impact that fluoroacetate-producing plants appear to have had on the genetic composition of indigenous Australian fauna.

The sensitivity of a number of avian species to the rabbit poison pindone (2-pivalyl-1,3-indandione) was investigated using increase of prothrombin time (PT) as an index of poisoning. Daily dose levels of pindone were 0.25 mg/kg for eagles, 4.0 mg/kg for magpies and 5.0 mg/kg for pigeons, parrots and ducks. Considerable species variation in response was observed, and within each species there was considerable individual variation in response to pindone. The PTs of magpies and ducks increased to approximately twice baseline levels. Significant elevations (4- to 7-fold) occurred in parrots, pigeons and eagles. Clinical symptoms were observed in only one species, the wedge-tailed eagle. Results of dosing trials indicate that all species tested are theoretically at risk of pindone poisoning, although the risk to some species is minimised by factors such as population size, food availability and bait placement.