New Zealand Journal of Ecology (2016) 40(1): 60- 64

A novel device for controlling brushtail possums (Trichosurus vulpecula)

Research Article
Helen Blackie 1,2*
Jamie MacKay 1,3
Brent Barrett 1
Shane Inder 4
Duncan MacMorran 2
Jennifer Bothwell 1
Mick Clout 3
Charles Eason 1,5
  1. Centre for Wildlife Management and Conservation, Lincoln University, PO Box 84, Lincoln 7647, New Zealand
  2. Connovation Ltd, PO Box 58613, Botany, Auckland 2163, New Zealand
  3. Centre for Biodiversity and Biosecurity, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
  4. Industrial Design and Innovation Lab, Faculty of Design and Creative Technologies, Auckland University of Technology, Auckland 1145, New Zealand
  5. Cawthron Institute, Private Bag 2, Nelson 7042, New Zealand
*  Corresponding author

Pen and small-scale field trials have been completed on a new, long-life, resetting toxin delivery system for brushtail possums (Trichosurus vulpecula). Devices are designed to attract and control possums over long periods of time with minimal input and maintenance. The units are species-specific, lightweight, environmentally robust, and have the ability to control 100 possums before requiring servicing. Devices dispense a measured dose (0.8 g) of a palatable gel containing 12.5% zinc phosphide (Zn3P2) onto a possum’s abdomen. Pen trial results demonstrated that after receiving a measured dose from these devices, 89% of nine possums groomed the gel from their fur, ingested it and died. The average time to death following ingestion of a lethal dose of zinc phosphide was 4.6 hours, a comparatively short timeframe compared to other control tools (specifically sodium fluoroacetate, cholecalciferol or brodifacoum). A small-scale field trial deploying 11 devices at 100-m intervals was run in an 11-ha mountain beech (Fuscospora cliffortioides) forest site. A sample of ten possums in the vicinity of these devices were collared with VHF-mortality sensors and, of the nine individuals with known fates, eight were killed shortly after interacting with a resetting delivery system.