Page content Page content Section navigation Topic navigation Accessibility keys Sitemap Search Contact us portal


Ferrets (Mustela furo), stoats (Mustela erminea) and weasels (Mustela nivalis vulgar).

Ferret, Stoat and Weasel Image

On this page: Identifying features, Responsibility for control, How to control mustelids, Useful contacts, Where to buy mustelid control products, Other publications

Download this factsheet

Identifying features


Male ferrets grow up to 44cm and females up to 37 cm in length. The undercoat is creamy yellow with long black guard hairs that give the ferret a dark appearance. Their legs and tail appear darker than the body, and the lighter facial region has a dark mask around the eyes and across the nose.


Stoats are smaller than ferrets. The males grow up to 30 cm and females up to 25 cm long. Stoats have long, thin bodies with smooth pointed heads, and their ears are short and rounded. Their fur is dark brown with creamy white under-parts. Stoats have relatively long tails with a bushy black tip.


Weasels are the smallest and least common mustelid in New Zealand. Males grow up to about 20 cm. Their fur is brown with white under parts, often broken by brown spots. Their tails are short, brown and tapering.

Responsibility for control

Mustelid control is the responsibility of land owners/occupiers. In specific areas Waikato Regional Council carries out limited control, along with possum and goat control. We provide advice and some assistance (for example control demonstrations) to interested parties carrying out mustelid control.

No one can farm, breed or sell ferrets, stoats or weasels unless authorised by the Department of Conservation.

How to control mustelids

Trapping - Fenn trap

The Fenn trap is designed to catch mustelids. There are two models:

  • the Mark 4, a smaller version for catching rats, stoats and weasels; and
  • the Mark 6, the larger version that will catch the smaller animals as well as ferrets and rabbits.

Both traps are RSPCA approved.

Placing the trap: Good trap sites for mustelids include: wood piles, small animal tracks that pass under fences, piles of stones, rabbit burrows and small drain pipes. Other areas include the edges of ponds and streams and under trees where the vegetation is short.

Making a tunnel: Mustelids cannot resist tunnels and frequently run through pipes, over logs, and in and out of holes. Setting your trap on a run, inside a pipe or tunnel, or down a rabbit burrow, will increase your changes of catching a mustelid.

You can make a tunnel out of drainage pipe, wood, field tiles, sticks etc.

The tunnel should be about one metre long and wide enough for the trap to be sprung inside of it (20 cm wide and 17 cm high for Mk 6 traps; 15 cm wide and 13 cm high for Mk 4 traps). The tunnel should have sides and a top – no bottom. Setting two traps in one tunnel may be more effective.

Setting the trap in a tunnel prevents accidental catches of other species and prevents children from stumbling over them.

Baiting the trap: Fresh rabbit meat, the entrails of poultry and eggs are attractive to mustelids. Place twigs and stones around the trap to guide the animal to it. Place the bait on or behind the trap in such a way so that the animal must walk over the trap to reach it.

Kills may be increased by dragging the bait around the trap site, leaving a blood trail. Baits should be replaced every two to three days, or in hot weather, every day.

Legal Requirement: all live capture traps must be checked daily.

Useful contacts

For additional advice and information and to obtain pest control products, contact your local farm supply store or nearest Biosecurity Animal Pest Contractor for the Waikato region.

Where to buy mustelid control products

Other publications

Regional Pest Management Strategy

Waikato Regional Council pest animal and plant publications

'What makes a pest a pest? - A guide to Waikato's pest management future' download, order or pick for free from our offices.