The Sensitivity of the Brushtail Possum (Trichosurus vulpecula) to 1080 Poison

A knowledge of the sensitivity of the brushtail possum (Trichosurus vulpecula) to 1080 poison is important as a basis for planning effective control campaigns. This study assesses the effects that experimental procedure may have on determining the LD50 of 1080 for brushtail possums and reports on the variation in sensitivity within and between different populations of the species in Australia, where it is indigenous. LD50s obtained ranged from 0.39–0.92 mg kg-1, with 95 % confidence limits of from 0.29–1.20 mg kg-1. These figures are similar to those obtained by Ministry of Agriculture and Fisheries researchers in New Zealand but are less than those obtained by the New Zealand Forest Service and bring into question which figures are valid for free-roaming possums in the bush. This is important in regard to the toxic loading of baits, particularly given the reported aversion by some possums to baits containing the recently increased concentration of 1080 recommended for possum control in New Zealand forest areas.