Why eradicate stoats?
Stoats are a threat to the native birds and other wildlife on Waiheke Island. Ground-nesting birds like the dotterel, ōi (grey-faced petrel) and kororā (little blue penguin), and hole-nesting birds such as kākā are particularly vulnerable, as they have very limited means of escaping stoat predation, particularly when rearing young.
Stoats are very agile and fast and require regular refuelling – males must eat a quarter of their body weight daily, while lactating females need to devour half of their body weight! Stoats that are unable to catch sufficient food will starve within 2 - 3 days.
Kākā and dotterel. Photos by Pete Rees
Despite being introduced to New Zealand to control rabbits, the major part of a stoat diet is native birds, followed by insects, mice, rabbits, and then rats.
Stoats can have very large home ranges and are excellent tree climbers. Stoats are fast breeding with highly developed reproductive systems - females are almost always pregnant. Males mate with the mother of a litter soon after she has given birth, then impregnate the baby female stoats in the litter.
The first part of the Te Korowai o Waiheke; Towards a Predator Free Waiheke programme is the permanent removal of stoats. We are eradicating stoats first because of the significant damage they do to our native wildlife and the low risk that they will be able to return to Waiheke once eradicated. We are also confident based on other island eradications in New Zealand that this is achievable.
Many of the islands surrounding Waiheke are already predator free and the distances between them mean it is unlikely that stoats will swim back. These islands have stoat traps on them to catch any swimming animals. Stoats generally swim one to three kilometres but have been known to swim up to five kilometres. In the Hauraki Gulf biosecurity prevention measures on commercial boats are already in place through the Pest Free Hauraki Gulf programme run by Auckland Council and the Department of Conservation.
Recreational boats are considered a low risk as stoats, weasels and ferrets have not been detected using these transport modes.
Like kākā and dotterel, grey-faced petrels and little blue penguins are particularly vulnerable to stoat predation.
King C. M. & J.E. Moody J. E. 1982a. The biology of the stoat (Mustela erminea) in the National Parks of New Zealand: I. General introduction. New Zealand Journal of Zoology, 1982, Vol. 9: 49-56
Report a mustelid sighting!
Mustelids are extremely nervous, aggressive and secretive. If you see a stoat, ferret or weasel please call us on
0800 BIRDSONG or email us on frank@tekorowaiowaiheke.org