Proceedings of the Vertebrate Pest Conference

Bennett’s wallaby (Macropus rufogriseus) was introduced to South Canterbury in New Zealand’s South Island in 1974. The species rapidly increased in numbers, and by the 1940s had increased to levels where it had become a significant agricultural pest. In 1947, a coordinated wallaby control program employing teams of shooters commenced. However, wallaby numbers stayed high, and it was not until the early 1960s when aerially sown 1080 baits were used that a significant reduction in wallaby numbers was achieved. However, the need to de-stock areas prior to application of the baits prompted fanners to demand control by shooting teams rather than poison in order to achieve ongoing control. Wallaby control in South Canterbury is managed under a Regional Pest Management Strategy, relying on shooting as the primary form of control, but using aerially distributed 1080 baits and 1080 gel applied to broadleaf foliage to a limited extent when and where necessary. Wallabies are continuing to expand their range into the central alpine region adjacent to South Canterbury where they are becoming a conservation threat on public lands. In this study, we re-analyzed 13 years of detailed hunting return data in order to derive a synoptic model of wallaby population growth relative to density and prevailing rainfall. We also estimated cost-effectiveness models for control employing shooting teams, aerially distributed 1080 baits, and 1080 gel applied to foliage. We then explored the cost-effectiveness of alternative strategies for wallaby control by combining the models predicting wallaby population growth with those predicting variation in the cost-effectiveness of available techniques. The implications of this study for ongoing wallaby control for mitigation of agricultural and conservation impacts are discussed.