Stopping mink in their tracks – tips and tricks of the trade

Karen Muller, Project Officer, Scottish Invasive Species Initiative.
May 2021

Sleek, dark brown fur, flashes of white under the chin and a bounding gate or streamlined-shape cutting through water – the invasive non-native American mink. In the last 50 years they have become a more common sight along our Scottish watercourses and coastlines than we – and our native wildlife – would like. 

The devastating impacts of this adaptable and ferocious predator are clearly apparent – mink predation contributing to significant declines of native wildlife species, particularly water voles and ground nesting birds.

Over the last 15 years much mink control has taken place in Scotland.  However as these are wily creatures who think nothing of travelling 80km to find new breeding territories and craftily avoid entering traps their removal is not straightforward.  So, here are some tips and hints from the Scottish Invasive Species Initiative for successful mink trapping and how to out-trick these irreverent tricksters.

Please note – this article is not a guide to trapping.  Trapping should only be undertaken by trained people who understand their responsibilities regarding animal welfare, humane dispatch and relevant legislation.

American mink (photo credit – Liam Skinner)

Understand your foe

Mink are very adept semi-aquatic predators, active during the day and night and feeding opportunistically on a wide range of prey, such as fish, amphibians, birds (and their eggs), rabbits and other small mammals.

They are solitary and territorial animals – a female territory will cover around 1-3kms while male territories are usually larger (5kms) and can span across several female territories.  It’s worth noting that territories in good quality habitats will be quickly recolonised if the original occupant has died or been removed.

A good territory will be close to freshwater and often along a river in low altitude farmland, marshland or woodland edge with a plentiful supply of food e.g. rabbits.  Coastal areas are also popular – but mink still need a freshwater source nearby to clean their coats regularly.

To trap or not to trap – that is the question

As traps must be checked every 24hrs trapping can be time consuming, so it is worth monitoring for mink presence first and only starting trapping when you know mink are in the neighbourhood.

Mink monitoring is done by using a floating raft with a clay pad – to record footprints.  The raft is easily switched to trapping mode by adding a live capture trap when you know mink are present.  Read more about mink monitoring rafts on our website.

The mink monitoring raft – the clay pad sits inside the tunnel.

It’s also worth remembering to keep in touch with neighbouring monitoring rafts – our mink control is part of a large scale effort and so if you find mink signs let your neighbours know so trapping effort can be co-ordinated. The chances are that, due to their transient nature the mink you detected might have already carried on upstream and already be in your neighbour’s patch!

Alternatively, you can use a trail camera, or look for field signs if you don’t have a monitoring raft.   Check muddy or sandy banks for tell-tale footprints, bridge arches or prominent rocks for scat and look for flattened trails on riverbanks. 

Key trapping times

The best times for catching mink are pre- and post- breeding periods when mink are mobile and so there is a greater likelihood of catching them. Trapping success at these times will have a greater impact on the overall mink population.

Between January and March, many mink are transient and travel widely outside of their territories – males searching for a mate and young females searching for a breeding territory. Catching mink at this time will avoid successful breeding and prevent new mink being added into the population mix.

In summer family groups emerge from the den and by early autumn young mink are starting to leave their natal home territory but still congregate quite locally. These juvenile mink are extremely inquisitive and naïve making them easier to catch – so from July – October is the second critical trapping time.

Young female mink caught in trap.

The ‘how’

There are many native and domestic animals which can frequent the same habitats as mink – so we use live-capture traps and release non-target species unharmed.  Placing the trap on a floating raft on water further reduces the likelihood of catching non-target species as many of these are less likely to make the swim to the raft and trap.

Always cover your trap with a wooden tunnel for shelter and securely tie both the trap and tunnel to the raft.  This prevents the trap being dislodged by an angry mink or another animal and avoids the risk of accidental drowning.  Raft and traps units should be disabled or removed if the river is going to be in flood.

Live capture trap set on a mink raft, under the tunnel.

Location, location, location

Finding the right spot in the river for your mink raft and trap is the number one deciding factor in capture success – so here’s some handy hints to help you site your kit effectively on the water:

  • Look for confluences, where two water bodies join – you are doubling your chances that a mink will come across the trap by following either of the rivers or burns.
  • Find freshwater sources along coastlines – sooner or later mink are bound to search them out and use them.
  • Use pinch points – where mink are naturally forced through smaller gaps – as mink traffic can be funnelled towards your trap.  These can be:
    • under/near bridges or on bridge foundations/arches
    • culverts
    • weirs
    • in-stream islands
    • inflows and outflows on lochs
  • Select a sheltered spot out of the main flow – mink are good swimmers but they are not daft and will use the most efficient route to pass through their territories. Slow glides and slack water which make for easier swimming are ideal.

Remember – the location is no good if you can’t safely reach it in both high and low flow conditions – double check this first.  Also ensure if placed near a structure like a bridge or culvert that your raft will not cause a blockage in a flood.

A perfect spot at the confluence of two water courses.

A raft set up won’t be suitable for all locations – sometimes you can set a ground trap.

In these cases, you need to think like a mink!  Consider the likely routes mink use to move around.  In coastal areas, on beaches, this could be along the bottom of cliffs or harbour walls or between rock outcrops or prominent rocks.  Inland look for trails through vegetation along the bank, along hedges or fence lines, or fallen logs and wood and rock piles – even better if you find a well-situated log or rock pile and can fit the trap amongst them.  A mink might go for a rummage there for their next meal.

Note – If using a ground trap ensure the location is not at risk of flooding or within the tidal area. If in doubt put your trap on a raft, tied with enough slack that the raft can move in the case of water levels rising unexpectedly.

Please keep in mind that, any spot, even if it ticks all the boxes above is likely to be of little use if it is in too public a place.  We have had equipment vandalised or removed in the past and, given that if you catch a mink it will need to be despatched this task is not one which should have an audience and you certainly do not want a member of the public approaching a trapped animal.  If in doubt – find another place.

Ground traps; under a rock (L) and in a well camouflaged tunnel (R)

So, you’ve found your spot; you’ve set up your trap – time to open the box of tricks! Read on.

Trapping Hacks

Mink are curious, and you may never need to reach deep into your bag of tricks.  But if after a few weeks you are not having success then it may be time to try something a little different.

Location and set up:

  • Move your raft slightly -Try swapping to the opposite bank or a move upstream or downstream by 200 metres. Mink are fickle and these moves can often make a difference!
  • Change the direction of the trap opening – Footprints on your clay pad may give a clue to the general direction of mink travel so switch things around to see if that helps.
  • Try a double ended trap – Set two rafts with two traps opening in opposite directions. Or if on land set two traps up back to back.
  • Use camouflage – Your mink might be shy, so blend the unit into the environment. Pile some vegetation on top of a floating raft and tunnel and weigh it down with rocks.  If on land, cover it with small logs, branches, or rocks.
  • Make it obvious – This is a bid of a reverse to the camouflage suggestion above but, in non-public areas, you could also play to the mink’s curiosity and have the raft/trap in plain sight.  Sometimes the animal can’t resist the urge to explore the new addition to its habitat.
  • Make the tunnel appealing – Stuff some dry grass or other vegetation between the trap and tunnel – it creates an appealing tunnel to explore and a trapped animal to make a cosy nest from material pulled through the cage.  Make sure vegetation won’t be a hindrance when it comes to animal dispatch.  There is an added bonus here – if you catch a mink this vegetation will be saturated with scent and might entice the next one to the trap too!
  • Make sure it’s stable – If trapping on land, make sure your trap is stable – use stones or wood if needed. A wobbly trap can dissuade a mink from entering it or worse, set the trap off when knocked from the outside.

Go mad with camouflage (L) or line the tunnel with dried grass (R)

Baiting is usually unnecessary but if you do feel you need a little bit of extra help, you can try baiting with food, visual attractants or scent:

  • Food – Stab a cat food pouch a few times and hang it in the back of the trap or season your raft with a bit of oil from a tin of sardines or something else debatably “delicious” smelling. Don’t use actual food – you’ll attract every animal in the neighbourhood!
  • Visual attractants – Hang a bit of tin foil or a budgie mirror in your trap to grab the mink’s attention – get creative!
  • Scent – A scent lure holds the biggest potential, because mustelids use scent marking to communicate with each other. So, use of scent can be effective in enticing territorial animals to investigate a trap more closely – even the wily ones that turn their noses up at anything else.  There are options of how to do this but whatever you do – wear gloves!

You can collect your own scent – though this often isn’t for the faint hearted.  You can –

  • Relocate scent doused vegetation, tunnels, or traps after a mink dispatch to a different raft – though that may be impractical on a day to day basis.
  • Harvest your own scent – This is perhaps not for the squeamish or faint nosed – but I have experimented with scent harvesting from dispatched mink. A biodegradable cigarette filter, held in forceps, is saturated with “Eau de mink” from their anal scent gland. This can be done by just bringing the filter contact with their anus or, if we take it a step further to harvest even more scent, can be brought into contact with a scent gland after it has been extracted from the mink.  Not for everyone this!

Wire is threaded through the filter which is then hung from the cage grid above the trap treadle to entice the mink to enter as it takes a closer sniff.  These “scent bombs” can be stored in sealed plastic bags and added to traps as needed. This method has been used in other mink eradication programmes in preference to baiting with food.  An advantage of scent is it is more likely to specifically attract mink compared to food aromas which may also attract non-target species such as rats, otters or the odd adventurous cat.

Finally, a tip that makes your life easier – especially if your trap is located on a small island, or in a difficult to reach areas.   Attach a flag to your trap door as a visual aid to check on the status of your trap – some trap designs are better suited to this than others, and some are not suited at all but it can be really helpful. When the trap door is open the flag is up, when the trap door closes the flag goes down and is no longer visible – time to check on the trap!  You may even be able to check on your flag with binoculars from a distance. Watch a video of Karen demonstrating the signal flag.

All of the above should give a good starting point.   But of course, sometimes you may still catch nothing – remember you are pursuing a wild animal which won’t always behave as we hope or expect it to.  Be flexible and try something new now and again.

A bit of patience and luck results in a capture.

Sometimes, of course, it’s not you or the trap itself.  Perhaps the mink was transient (just moving through) and won’t come back, maybe it found itself in a different trap in the area or met its demise in a natural way, or possibly there is too much disturbance at your location and the mink doesn’t take time to investigate.  Or maybe you have a wily and cautious animal which simply won’t enter the trap pretty much whatever you do!

Despite our best efforts, there is always a little bit of luck and patience involved in mink trapping. Remember no signs of mink is a good sign – but please remain vigilant so we are ready when an animal heads your way, don’t get disheartened and don’t give up.  And while you’re there,  remember to take a moment to enjoy the native plants and animals living and thriving around you, breathe some fresh air, listen to the birds and relish the opportunity to get to know parts of your local river better you’ve never explored before.  Nature is good for you!

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Read more about the Scottish Invasive Species Initiative Mink Control Project on our website (www.invasivespecies.scot). Most of our rafts and traps are looked after by volunteers, if you’d like to find out more about getting involved read more about volunteering or contact us on sisi@nature.scot

Please note – our mink project only operates in Northern Scotland – specifically Highland/Eastern Perthshire, Angus, Aberdeenshire, Moray, Inverness-shire, Ross-shire and West Sutherland.

Adventures with Bonnie – training a mink detection dog

Mirella Toth, Project Officer, Scottish Invasive Species Initiative
October 2020

I started to volunteer for the Scottish Invasive Species Initiative in March 2019 and have loved being involved ever since. I am from Hungary, am a motivated practical conservationist and love being outdoors and feeling like I’m doing something that matters.  I learnt a lot being a volunteer and I was so pleased that I had the opportunity to join the Scottish Invasive Species Initiative team this summer as a Seasonal Project Officer and learn even more.  As well as controlling invasive plants, part of my job was to work on the American mink control project, finding and catching invasive mink in the Spey and Findhorn, Nairn and Lossie catchments.  As well as conservation I have another passion – dog handling and training which I was able to use this summer.

Bonnie, a Hungarian wirehaired Vizsla

I used to train dogs for hunting as well as having over 7 years’ experience training police and truffle dogs in Hungary.  When my boyfriend took a detection dog handler job with the Orkney Stoat Project, it opened my eyes to the possible use of dogs to help find American mink in the field.  Imagine how amazing it would be to walk along the riverbanks, have a dog indicate the presence of mink and so know where to place our traps.  I thought this could be my own project within the Scottish Invasive Species Initiative and so, when I had the opportunity to get a puppy my journey with Bonnie started.  

Bonnie at 3 months old

Bonnie is a Hungarian wirehaired Vizsla. I have previous experience with the breed – they are excellent hunting dogs and good trackers which are ideal characteristics for my planned mink detection role. She is now 1 year old and is amazing.  I started her obedience training when she was around 3 months old and moved on to search work a little later.  Because of her young age she can still be easily distracted – a butterfly fluttering by or even her own shadow are sometimes more interesting distractions which makes the training more fun from my point of view.  It is always a pleasure being around Vizsla’s – they are so charismatic.

I started her search training when she was 6 months old. Whenever I am working with her I put a harness on to show her that she is working – if she has a harness then we are working if not then the walks just for fun!   My priority was to get her to confidently detect any sign of mink in the field.  I started her training in my garden with a dead mink – which she was really interested in – and then later moving out and progressing to the banks of the River Spey where we could look to find some real-life mink tracks and signs.

Bonnie in training

Bonnie took to the job really well and during the summer she was a huge help to me when on the trail of the mink.  When our volunteers on the River Spey found mink signs on their monitoring rafts it was up to me to put out traps in the area to try and remove the culprit. Initially (pre-Bonnie!) I spent hours looking for mink tracks and signs on the ground and, using my experience and knowledge, set my trap in a suitable place. I then waited and checked the trap each day but didn’t catch anything – the mink can be an elusive quarry. Towards the end of the summer I felt Bonnie was ready for her first real mink mission on the River Spey.  I took her to the river and she soon indicated on a spot on the riverbank – so I moved the trap there.  The result? Success – I caught not just one, but to date, four mink from Bonnie’s trap!

Success! – a mink caught in Bonnie’s trap on the River Spey

But her success on the Spey was not just luck. On the River Nairn I had the same situation.  Volunteers reported mink sightings and although I had my traps out and set after weeks and weeks, nothing had been caught. We decided a change of plan was needed and that we should move the traps to a new location and so I put Bonnie in the car and we headed to the river. Again, she found a minky spot and I moved the trap there based on her advice!  A couple of days later we had caught a mink in it.

Mirella and Bonnie – in the car on the way to the River Nairn

I am very happy with the results from this summer and with Bonnie’s progress. There are so many factors to think about when locating a trap to try and increase the likelihood of catching the mink and, even for the experienced, there is still a good bit of luck required!  I think that even an experienced trapper would save so much time and effort with the help of a trained dog like mine.  Although I’m moving to a new job for the winter, I’m sure Bonnie will come back and find more American mink for the project in the future.  Watch this space!

Bonnie checking a trap is placed to her satisfaction!

If you’d like to find out more about the Mink Control Project or are interesting in volunteering and monitoring a mink raft or trap visit – www.invasivespecies.scot or contact us on sisi@nature.scot

Trail cameras – our secret agents in the field

Jack Farge, Project Officer, Scottish Invasive Species Initiative
September 2020

Trail cameras are handy gadgets that we’ve found increasingly useful here at the Scottish Invasive Species Initiative – so handy in fact that we thought we’d like to tell you a bit about how we use them and what they show us.

The cameras are fixed in place and are triggered by motion sensors which makes them useful for collecting footage of elusive animals such as American mink – a non-native invasive species that we are trying to locate and trap – which we otherwise wouldn’t see.  Day or night, rain or shine, our trail cameras are on the job!

Mink mysteries
Our first step in mink monitoring uses a simple, low tech method which can be widely rolled out – the mink raft – this relies on an extensive network of dedicated volunteers to confirm the presence or absence of mink across our project area using these floating rafts. Our fabulous volunteers look after these rafts which consist of a tunnel, with a clay pad inside, to collect the footprints of mink, or any animal, that walks through the tunnel (left image below).  Where the presence of mink is confirmed we place live-capture traps onto the raft (right image below) and see if we can catch the mink – which are then humanely dispatched. Mink are naturally curious and usually check out the tunnels on their own accord but they are also sneaky and wily and occasionally they taunt and deceive us – which is where trail cameras come in.

Capturing video footage of mink can provide an insight into their behaviour and help us identify why – even though we know mink are present – they are not venturing into our traps. The raft/trap unit could be positioned on the wrong riverbank or pointing downstream when it would be better pointing upstream – whatever the issue sometimes the trail camera can help us solve the mystery. 

Click video to watch (on YouTube) or scroll to bottom of article


We also have had to solve the case of the disappearing bait!  We couldn’t work out how bait kept disappearing from inside the trap without the trap being triggered and the door closing! Trail camera to the rescue – it turned out that an otter was sneaking in and having a nice snack on the bait while it held the trap open with its large back!

Click video to watch (on YouTube) or scroll to bottom of article

Snapping Sheep
Trail cameras are also proving really useful at our sheep trial site at Macduff where we are working with a local farmer and the University of Aberdeen to see how best sheep can be used to control Giant hogweed through a managed grazing regime. We’ve installed several cameras around the site which allow us to monitor the sheep’s behaviour, without human influence, by capturing videos of the sheep in grazing action. We are also using trail cameras to gather a visual record of the impact of the sheep by capturing time lapse footage of their grazing progress each day.

Click video to watch (on YouTube) or scroll to bottom of article

What else is out there?
Sometimes it isn’t just mink we find.  One of our mink raft volunteers recently asked to borrow a trail camera after suspecting water voles were in the area. Water voles are one of our most threatened native mammals, largely due to mink predation, so it is great to see if they are making a comeback in areas where we are controlling mink.  We were happy to lend a camera as gaining familiarity with these gadgets is  a great skill for volunteers to learn as well as providing great images for the project.  She didn’t get water voles on film but instead found something even rarer, this amazing footage of a family of Scottish wildcats! (N.B. Later confirmed as hybrid wildcats).

Click video to watch (on YouTube) or scroll to bottom of article

Such footage of our native wildlife is really useful and valuable; it can be important for other conservation projects, we can use it on social media to help raise awareness of our native wildlife and it can help engage people with their local environment.  We’ve also found that when working in schools showing a class of children video footage of an American mink and an otter is not only helpful in explaining the difference between the two species, but also great at grabbing and focussing their attention!

You can watch more wildlife clips on the Wildlife Watcher page on our website or on our YouTube channel.

Give it a go!
If you’ve got your own trail camera or can borrow one and would like to learn more about how and where to set it, check out our helpful hints in the Alien Detectives ‘Caught on Camera’ activity.  If you get some animal footage you’d like us to see and share then get in touch with us at the email address below – we’d love to see what you find!

If you’d like to find out more about our mink control project or are interested in monitoring a mink raft find out more at www.invasivespecies.scot or contact us on sisi@nature.scot

I like to think this mink knew that is was on camera!
This cheeky otter was stealing all the bait out of the mink trap!
When they get stuck in these ravenous ruminants make short work of giant hogweed.
This footage was really useful for the Scottish Wildcat Action project.