Environment

Stoat

Stoat.Stoat.

Common names:
Stoat, mustelid

 

Scientific name:
Mustela ermina

 

Regional classification:
Cost recovery and community control

 

 

Description

Stoats and weasels have similar colouring but stoats at 40cm are larger and therefore able to kill larger prey, giving them a wider variety of food so they survive in much higher numbers than weasels. 

 

Young stoats can travel more than 20 km. 

 

Size and colour

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.

Stoats are similar in colour to weasels but are larger - weasel (left), stoat (middle) and ferret (right).Stoats are similar in colour to weasels but are larger - weasel (left), stoat (middle) and ferret (right).

 

Breeding

Stoats have one or two litters a year, with four to eight young in each litter.

 

Field sign

Mustelid scats (droppings) are long and thin, often with a characteristic tapering twist at each end.  They are filled with fur, feathers and bone fragments and are hard and black when dry. 

 

Mustelids secrete onto their scats a thick oily yellow powerful smelling fluid called musk.  Scats are often placed in conspicuous positions such as in the middle of a track as a sign to other mustelids in the area.

 

Mustelids characteristically eat the flesh from the neck and head area of their prey.

Why are they a problem?

Mustelids feed on small animals including:

  • rabbits
  • rodents
  • possums
  • birds

They also feed on whatever opportunity offers, including:

  • eggs
  • lizards
  • frogs
  • insects

They have also been implicated in the transmission of TB to cattle.

Recommended control methods

The English Fenn trap is the best method of trapping mustelids.  It is a steel spring trap which kills small animals by breaking their backs.  These traps can be ordered from the Northland Regional Council. 

 

Fenn traps come in two sizes:

  • Mark 4 is a smaller size best suited to small weasels and stoats.
  • Mark 6 trap will handle the larger ferret, and is also suitable for smaller animals.

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
  • 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 chances 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 Mark 6 traps;
  • 15 cm wide and 13 cm high for Mark 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.

 

Traps should be set in places used by mustelids or where they have been seen.

 

Baiting the trap

The best bait for mustelids include:

  • fresh rabbit
  • liver
  • eggs
  • the entrails of poultry
  • fish flavoured cat food also works well

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.

 

A piece of bait or fish can be dragged around on a piece of string to make a scent or blood trail leading to the trap.

 

Baits should be replaced every two to three days, or in hot weather, every day.

Note:  All traps must be checked at least once every 24 hours under the Animal Protection Act 1960, Section 6.

 

Shooting

Mustelids are often encountered while spotlighting rabbits and possums and can be shot, although shooting alone is not an effective control measure.  

 

Poisoning

There is no poison available which private individuals can use on mustelids.  Occasionally mustelids die of secondary poisoning after eating the carcasses of rabbits and possums killed by poison.

 

Find out more: Download pest animal control publications

More information

For further information or control advice please contact one of our Biosecurity Officers at the Northland Regional Council on 0800 002 004:

  • Whangarei: Carl Cooper and Steve Henderson
  • Dargaville: Paul Ralph
  • Kaitaia: Mike Knight

 

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