Stoat with chick
Image: David Hallett © 

Introduction

Stoats are 'public enemy number one' for New Zealand birds.

Highlights

The stoat is a member of the mustelid family, along with weasels and ferrets. It was introduced to New Zealand in the 1880s to control rabbits and hares but is now a fierce predator of our native species. 

The threat

Stoats are implicated in the extinction of some indigenous bird species (bush wren, laughing owl, native thrush) and as the major cause of decline of many others (South Island kōkako, takahē, kākā, mohua, Hutton's shearwater, kākāpo, kākāriki and some kiwi species).

They are known predators of many other native birds and feed heavily on reptiles and invertebrates.

Predation of young kiwi, chiefly by stoats, is currently the most important factor contributing to the continuing decline of mainland kiwi populations.

Stoats are agile climbers, and hunt at any time, day or night. They are also strong swimmers, known to have crossed water gaps of up to 1.1 km to reach islands.

This video shows stoats eating rock wrens in the Upper Hollyford Valley, Fiordland. Every rock wren nest that DOC monitored that year failed, and predation by stoats was the primary cause.

Description

Stoats and weasels are similar in colour and general appearance, but stoats are larger, have longer tails and a straight line where the brown fur on their backs meets the white belly fur.

The stoat is reddish-brown above, white to yellowish underneath, and has a long tail relative to weasels, with a distinctive and obvious bushy black tip. In very cold, snow-prone areas some stoats develop a pure white winter fur, though this is rare in New Zealand.

It is 350-400 mm long from nose to tip of tail. Males are generally larger than females. Average weight of males is around 325 g and females 205 g, though this may vary from region to region.

Habitat

Stoats live in any habitat where they can find prey. In New Zealand they care found anywhere from beaches to remote high country, at any altitude up to and beyond the tree-line, in any kind of forest – exotic or native, in scrub, dunes, tussock, and farm pastures. They are known to occur near human settlements. In open country they are less common than ferrets, but in the forest they are more common.

Den sites are well hidden and changed frequently. Home ranges are generally large 60-200 ha, and considerable distances can be travelled in short periods. Stoats have excellent powers of dispersal and individual juveniles have been known to travel over 70 km in two weeks.

You can help to control stoats

Regular predator control will help to control stoat numbers and get us closer to the Predator Free 2050 goal. 

DOC's work

Read stories about DOC's work

Battle for our Birds

High levels of seed production ('mast') in our beech forests trigger rodent and stoat explosions.

When seed supplies run out these predators will turn on endangered birds such as mōhua, kākā, kea, whio and kiwi along with other at risk species like bats and land snails.

To protect our native wildlife, DOC is implementing the 'Battle for our Birds' predator control programme.

Battle for our Birds programme


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