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Why is it a problem?


Introduced into New Zealand in the mid-1800s, the ferret is a member of the mustelid family, along with the smaller weasels and stoats. Like all mustelids, they’re highly intelligent and willing to attack and kill much larger prey,  ferrets specifically target rabbits. However, they will opportunistically hunt birds and are known to target braided river birds breeding on riverbeds. They’re implicated in the rapid decline of the critically endangered black stilt/kakī.


Ferrets are much larger and ‘stockier’ (see here for a comparison) than stoats. The colour varies, with a typical white or cream undercoat and a variable quantity of longer dark guard hairs, giving some animals a black looking appearance while others appear almost white. The tail is generally but not always uniformly dark. There is a variable dark mask across the eyes and above the nose.

The body length is around 320-460mm plus tail of 110-180mm. Males are noticeably larger than females, averaging 1.1-1.3 kg (max 1.85 kg) with females ranging from 400-1,100 grams.

Where is it found?

Found on all braided rivers throughout New Zealand.

Ferret targeting a banded dotterel nest on a riverbed.

Conservation activities

More information