Record results in fight to control Scotland's mink menace

The Herald Scotland

03-05-2025

There, in idyllic surroundings with just nature and her pony for company, Jacqueline has 'murder' on her mind.
Her target is the pesky American mink, descendants of fur fan escapees from years ago that have infiltrated the burn and countless other waterways the length and breadth of Scotland.
Should she happen to find one in one of the small traps laid by the side of the burn, she would be more than happy to take out her air pistol and complete the deadly deed.
Jacqueline Merrick with her pony, Tweed, carry out daily 'mink patrols' around her Perthshire cabin (Image: Contributed - Jacqueline Merrick)
At 70, Jacqueline could easily opt to take it easy. Instead she is just one of a growing army of volunteers at the frontline in the long battle to track down and dispatch pesky American mink.
Their efforts combined with increasing use of technology that instantly raises the alarm whenever one of the hundreds of traps dotted around a vast Highland area is triggered, is now paying off.
After decades of trying to get to grips with one of the country's most troublesome invasive species, the Scottish Invasive Species Initiative last year racked up its best year ever.
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Using new 'smart traps' fitted with alarms, hundreds of wooden mink rafts built by helpers, and thousands of hours spent by volunteers to monitor the traps in hard-to-reach rural spots, the project more than doubled the number of mink trapped last year compared to the previous one.
In what turned out to be a record-breaking year for mink catches, the SISI workers and army of volunteers caught and dispatched 242 of the pests, an impressive increase on its previous highest tally of 169 recorded in 2020.
On the Spey alone, 38 mink were caught and killed – another record-breaking figure. Across the Dee and the Don, 50 were captured.
An American mink on the River Devon. (Image: Keith Broomfield)
It was also a record year for volunteer involvement: last year 353 volunteers like Jacqueline devoted hours to scanning their local patches for signs of American mink, checking the monitoring rafts set up to capture mink tracks and mink traps, and raising the alarm should any be found.
In all, there were over 100 more volunteers on mink patrol across the SISI's north of Scotland project compared to the previous year.
Key to such a successful year has been a determined community effort.
From Cromarty to Brechin and Elgin, more than a dozen Men's Sheds, groups which offer men a place to gather to repair furniture or make bird nests and garden chairs, and Wood RecyclAbility in Ellon, a similar community group, have built hundreds of mink rafts.
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Consisting of a wooden tunnel with a clay pad on which inquisitive visitors leave their paw prints, they are left at key spots where American mink are thought to be.
Their input meant the number of traps set at waterways across the project site - stretching from Perth to Durness in the north and towards Wester Ross and taking in 43 river catchments - soared from 217 in 2023, to 419.
Last year's successes - although still a drop in the ocean - already seem on course to be matched in 2025: by the end of March, 56 mink had been captured.
(Image: Brian Macfarlane)
With their brown soft fur and snowy white chin, American mink may look endearing but they are vicious predators which eat their way through ground nesting birds and their eggs, small mammals, fish – including salmon - and domestic fowl such as chickens and ducks.
Their main prey, however, are water voles, the small beaver-like mammals whose burrowing and feeding habits support a host of other riverbank animals and plants.
Familiar to generations as 'Ratty' thanks to the Wind in the Willows character, water vole numbers have faced a 95% loss of range in the past century with much of the pressure on their numbers attributed to American mink.
Today's wild American mink either escaped or were deliberately freed from farms set up in Scotland in the late 1930s to supply fashion demand for their silky fur.
By the 1980s they had already spread north of the Great Glen.
Similar to otters, they are strong swimmers and can travel long distances in search of food and new breeding grounds.
The only way to effectively control their spread is to trap and kill them.
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The challenge is huge: American mink have been found from Dumfries and Galloway, across the Firth of Forth area, beside the Forth and Clyde Canal, and in rivers and burns across parts of the Highlands.
Three years ago, American mink were found on Isle Martin, in the Summer Isles. They have also turned up on the Caledonian Canal and River Ness. It took years of effort to eradicate wild American mink that had escaped from fur farms on the Western Isles.
A key focus of the current SISI project is to focus on trying to curb their progress further north and prevent them hitching a ride to west coast islands.
Water voles are the main prey for invasive American mink (Image: Ian Gray)
With breeding season now underway and each pair capable of producing between four to six young, Callum Sinclair, SISI project manager, says snaring them now, before they are able to infiltrate new areas means every sighting is crucial.
'Mink breed between May and June, then in August and September move on to seek territories for the next breeding season.
'Around 80% of them will move about 20km to find new breeding location, but 20% can travel 80km and more to find new area,' he says.
'They are fantastic animals and brilliant predators, but they are also undesirables.'
A major step forward in controlling numbers has been the introduction of the new smart traps.
Until recently, mink rafts fitted with clay or sand trays were only checked every couple of weeks for signs of animal prints. Only then a 'live trap' would be set and regularly checked for captures.
Anything other than mink could then be released or, if a mink was trapped, dealt with quickly to avoid stress.
(Image: Waterlife Recovery Trust)
But the system was 'hit or miss', required constant monitoring of traps which were often in hard to reach spots.
'Now, instead of hoping we get lucky, we can set traps with remote units fitted, so as soon as an animal comes around and is captured, a notification lets us and the volunteers in the area know.
"We can then release the animal if it's not one we're after, or deal with it on site if it is.
'We are working in 'real time'.'
The new system takes the 'chance' element out of catching mink and makes dealing with captured animals more effective and efficient.
A mink raft used to monitor the presence of American mink
'We still have volunteers who prefer old school monitoring and who look for footprints and set the trap after that,' he says.
'And in some areas there's not a reliable enough phone signal for the trap to work.
'But regardless of how we operate - whether it's a trap we check daily or operated with remote unit – we still have to check every cage and every trap every 24 hours, so if anything is there it's dealt with humanely.'
It's where volunteers like Jacqueline come in.
She carries out a daily 'mink patrol' to check two traps on Balnock Burn near her Glen Derby log cabin home on the outskirts of Kirkmichael, taking Tweed along for the ride.
Jacqueline Merrick's Highland pony, Tweed, is at the forefront of the fight against invasive American mink (Image: Scottish Invasive Species Initiative) Although the traps she checks are fitted with the new equipment to instantly raise the alarm should an animal be caught, she prefers her daily check just in case the local mobile phone signal it requires to work, has dropped off.
Having farmed in the south west of England for 40 years and also worked as a field ecologist, she knows the damage that American mink can do.
'The water vole was declared extinct in Cornwall 25 years ago and the primary cause was the American mink,' she says.
One of two mink traps on Balnock Burn (Image: Jacqueline Merrick)
'A lot of people thought that because Cornwall has sea on three sides, it would control them. But it didn't.
'Almost everyone has heard of Wind in the Willows, and the character Ratty, which was a water vole.
'The fact that they were extinct in Cornwall and that predators like American mink are one of the main reasons, has made me passionate about them.'
When Jacqueline moved to her Perthshire rural log cabin home, she was shocked to be walking one day and sense the distinctive whiff of American mink scat.
Furious the pests were in the area, she offered her support to SISI.
In recent weeks, she found a female mink in one trap, which was duly dispatched thanks to a neighbour.
But she now has her own air pistol licence so, if need be, she can carry out the deed herself.
A female mink recently caught in a trap on Balnock Burn (Image: Jacqueline Merrick)
Not everyone in her social circle finds the grim task of dispatching one species even to help another palatable, she says.
But, she argues: 'Mink is a non-native carnivore that has decimated the population of other species.
'I've not yet seen a water vole near where I live.
'It is invaluable work and I'm so pleased that I was able to get involved.
'I feel lucky that I can go out with my little pony and ride to the burn to check the trap.'
Find out more about the Scottish Invasive Species Initiative work to control American mink here
Report a sighting of wild American mink here