The project seeks to enhance the ecological values of Secretary Island by eradicating or controlling stoats and deer to a level where they no longer impact on the island’s ecosystem.
Secretary Island (8,140 ha) is situated on the Fiordland coast at the entrance to Doubtful Sound. It’s the third highest island in New Zealand, rising sharply to a height of 1,196 m.
The only animal pests present on the island are deer and stoats. The absence of possums, rodents and cats has made the island a refuge for a diverse range of invertebrates, such as the knobbled weevil, cave wētā and tunnel web spider. There are also significant plant species which thrive in the absence of possum browsing, such as mistletoes and mountain lancewood.
Some animal pests did make it to Secretary Island, stoats in the early 1900s and red deer in the 1960s.
With its large size and few pests, Secretary Island offered exciting opportunities as a conservation sanctuary, but first the stoats and deer had to be controlled.
Stoats are currently controlled at very low numbers and there are no breeding deer on the island.
The restoration of Secretary Island began in 2005. Controlling stoat and deer numbers on such a large, steep island was always going to be huge challenge. The successful outcome would take over ten years of hard work and the use of groundbreaking methods:
Now, Secretary Island is fulfilling its role as a sanctuary for threatened species, with translocations of mohua, North Island kōkako, South Island robin and rock wren. Native species already present, including Fiordland skink, weka, bellbird and kākā, are also responding positively to the reduction in stoat numbers.
The native plant species once vulnerable to deer browse, including native ferns, broadleaf, māhoe and kāmahi are thriving.
Biosecurity measures on Secretary Island are critical to prevent the introduction of pest animals and plants. It’s important that all visitors understand the biosecurity risks and know how to prevent the introduction of seeds and animal pests, such as rodents.