Ferret (Mustela furo)
  • Has a creamy yellow woolly undercoat, interspersed with long contour hairs which are black at the tip, giving a general dark appearance.
  • The legs and tail appear darker than the body.
  • The lighter facial region has as dark, mask around the eyes and across the nose.
  • The ferret is the largest of the mustelids in New Zealand, with males averaging 60cm long and 1240g, with females 48cm long and 620g.
  • They are about the size of a small cat.
  • As the ferret is more heavily built that other mustelids, they don’t tend to climb and are frequently found in rabbit burrows.
  • Habit includes pasture, rough grassland, riverbeds, scrub land, forest fringes, and in recent times have been found deep within forests.
  • They are often found near human settlement where there is kitchen waste, poultry and pet rabbits.
  • They are also found as escapees near fitch farms.
Stoat (Mustela ermina)
  • Much smaller than the ferret.
  • Males are 40cm long and weigh 350g, whereas females are 33cm long and weigh 240g.
  • Stoats are dark brown with cream white underparts and a bushy black tipped tail.
  • Some stoats turn white in winter particularly in the South Island.
  • Habitat includes beaches, high country, exotic and native forests, scrub, dunes, tussock, farm pastures and near human settlements.
  • They are less common in open country and more prevalent in forests.
Weasel (Mustela nivalis)
  • The smallest of the mustelids averaging 20cm long.
  • Males weigh 150g and females 80g.
  • Weasels are brown with light underparts, very much like a stoat but the tail is short, wholly brown and tapered.
  • Unlike the stoat, the white underparts are often broken with brown spots.
  • Scarce and rather erratic in distribution.
Control methods
  • What you use will depend on whether there’s a need to protect non-target species. Remember that a baited trap will attract cats, dogs, hedghogs, and more, and of course be a real danger to children. Mustelids cannot resist tunnels and use of trap covers will assist catching them.
When to trap
  • Experience shows the optimum time for mustelids is from February to April.
  • But if they are predating birds or poultry, action must be taken immediately.
  • What mustelids like to eat
  • Small animals and birds are the main diet.
  • Rabbits, especially small ones are their main diet.
  • Rats, mice and hares are also eaten freely.
  • Ferrets being larger tend to take the large animals.
  • Birds eaten are mainly small native and introduced species although the ferret is well known for chicken raiding. All three mustelids will eat carrion although they prefer freshly killed food.
Baits for mustelids
  • Baits work well when feed is scarce.
  • Pieces or rabbit, hare, possum or poultry, particularly the liver or entrails, whole eggs, eggs broken over traps, rabbit or poultry bled on to traps, and canned fish-based cat foods.
  • Kills can be increased if you make a blood trail to the trap site.
  • Drag a dead rabbit or poultry carcass around set traps.
  • Put rabbit or poultry intestines in a bag and drag along.
  • When trapping mustelids on heat, drip urine of those species over traps to attract males.
  • Replace baits every 2-3 days, but in hot weather this may have to be daily.
  • Baits can be attached high above and behind the trap. For example - tie a fowl or rabbit to a stake so that it hangs 50-60cm above the ground and set a number of traps around it.
  • Make sure children cannot encounter traps or baits.
Where to set traps
  • Put traps on:
  • Stock tracks
  • In rabbit burrows
  • On small animal tracks that bypass fences
  • Small drain pipes that travel under roads
  • Under trees where vegetation is short.
  • In shelter belts and hedges
  • Along stream edges, rivers and ponds
  • In woodpiles and in piles of rocks
  • Around farm buildings
  • Around poultry houses or rabbit hutches
  • Place rocks and branches around the trap to guide the predator over the trap plate as it approaches the bait.
Trap placement
  • When setting traps, set them in lines of 10 or 20, and approximately 100 m apart.
  • This equates to a trap line of 1-2 km.
  • Mark every 5th trap or each individual trap to prevent you missing traps.
  • Place a board across a stream and place a trap cover on it, then the animal crossing the stream will enter the trap tunnel and be caught.
Trap maintenance
  • If you buy new traps, it’s important to remove any smells of oil, etc used in manufacture.
  • Wash the oil off with turpentine and then wash the trap well.
  • Or bury the trap for several weeks.
General comments
  • If you come across a sprung trap, record and reset it.
  • If you come across an unsprung trap with bait removed, reset it.
  • Then try to work out what went wrong. It could be:
  • You set the catch too heavy
  • The mustelid was able to approach the trap and steal the bait.
  • Then reset the trap incorporating the improvement.
  • If the trap has not been set off after several days, it’s advisable to reset the trap when re-baiting.

Information provided by Pest Management Services, PO Box 121, Waikanae, Kapiti, New Zealand, Phone (04) 293-1392. Fax (04) 293-1392 Mobile 025-454-810.
Email This email address is being protected from spambots. You need JavaScript enabled to view it.
Manager Lyn Nicholls will be happy to answer any questions on pests that may invade your property.

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