Eradication of introduced Australian marsupials (brushtail possum and brushtailed rock wallaby) from Rangitoto and Motutapu Islands, New Zealand

In 1990 the New Zealand Department of Conservation began an operation to eradicate the common brushtail possum (Trichosurus vulpecular) and brushtailed rock wallaby (Petrogale penicillata penicillata) from Rangitoto and Motutapu Islands in the Hauraki Gulf of Auckland. The operation began with a 1080 aerial drop on Rangitoto Island, achieving an estimated 93 percent kill of possums and wallabies. This was followed from 1990 to 1997 by ground work on both islands to complete the eradication of both species. Methods used were trapping, cyanide poisoning, dogs and spotlight shooting. This was followed by several years of ground monitoring and mop-up operations. Aerial surveillance, using a Forward Looking Infrared (FLIR) camera, was also conducted on two occasions to detect surviving animals. A Differential Global Positioning System (DGPS) (a navigational aid) logged flight lines and animals sighted. This was then interfaced on video footage so that survey data could be displayed in real time. The hunting team and their dogs were expected to operate under the harsh conditions of Rangitoto Island’s rugged volcanic terrain. There were successes and failures with the multiple field methods employed in this operation. Results from a recent survey have indicated that the eradication of an estimated 21,000 possums and 12,500 wallabies was achieved in the eight years of the operation. The eradication operation has been successful in restoring the previously degenerating Metrosideros forest on Rangitoto and Motutapu Islands.

Author Mowbray, S. C.
Year 2002
Secondary title International Conference on Eradication of Island Invasives
Publisher IUCN Invasive Species Specialist Group
Pages 226-232
Control method Integrated Pest Management
Region NZ