American mink: The 'opportunistic predator' flourishing in Ireland

American mink are now widespread in both Northern Ireland and the Republic

In a quiet County Tyrone valley on the outskirts of Plumbridge, lies Butterlope Farm.

Surrounded by the Sperrin Mountains, it's just 18 miles from the county town of Omagh.

And it is there that the story begins of how the American Mink - described as an aggressive predator and threat to native wildlife - came to flourish in the wild in Northern Ireland.

Butterlope is a working farm but it also provides education and training for adults with learning disabilities and mental health issues.

Part of that is working with the poultry on the farm - on two separate occasions the farm's hens have been attacked.

Annie Mullan, manager and tutor at Butterlope, told BBC News NI: "Both times the mink killed all of our hens - around a dozen each time."

A mink attack is different to that of other predators, she said.

"You know when it's a mink that has attacked because of the puncture wounds to the neck," she added.

Annie and her colleagues have worked hard to mink proof the farm's coop since the attacks two years ago and are, naturally enough, on their guard.

"The first thing we do every morning is check the hens," she said.

Her view is that, in the interests of wider conservation, the time may have come for authorities to consider controlling the mink population.

There have been efforts to do so in other parts of the UK.

When did the American mink arrive?

American mink were introduced into Ireland for fur farming in the 1950s. Over time, some escaped and some were deliberately released.

In 1961, 30 mink escaped from a farm in Omagh - the first documented escape from a fur farm in Northern Ireland.

They quickly became established in the wider countryside.

By the end of the decade the Belfast Telegraph was reporting that the "severity" of their presence was being felt on the banks of the River Strule.

The Duke of Abercorn, the paper reported, had lost 32 pheasant chicks and two broody hens to mink attacks at his Barons Court estate that year.

Mink farming has since been banned on both sides of the border but feral American mink are now widespread on the island of Ireland, according to the National Biodiversity Data Centre.

A threat to fish as well as to ducks and other birds, mink are prolific breeders. And, with no natural predators, their numbers have flourished.

"Mink are opportunistic predators that can impact on native wildlife, as with any other invasive species," a spokeswoman for Stormont's Department of Agriculture, Environment and Rural Affairs (Daera) said.

The department carries out its own control on the estates, parks and fish farms it owns and it "encourages landowners to control mink on their properties for the protection of native biodiversity".

The department currently has no plans for a wider mink control campaign, the spokeswoman said.

Feral American mink populations have spread across the island of Ireland

In the Republic of Ireland, discussions have previously taken place about how the mink could be eradicated completely. But that has been ruled out due to cost.

Ger O'Donnell, the National Parks and Wildlife Service (NPWS) manager in the north west, monitors territory including the Inch Wildfowl Reserve in County Donegal, where a number of mink have been spotted in recent weeks.

"Two things set them apart from other predators," he said.

"One, they are not meant to be here, and two they have a particular versatility - [they are] as at home in the water as they are on land."

Inch Wildfowl Reserve has special status under EU law because of its importance to a number of bird species

As predators go, he added, they are "on top of their game".

Inch is designated a Special Protection Area (SPA) under the EU Birds Directive and home to curlews, corncrakes, black headed gulls and snipe, among others.

"All water fowl and ground-nesting birds are vulnerable to mink," Ger said.

Trappers work during breeding season to control the mink; other measures have included a predator fence being erected on the island site.

Curlew numbers have been in decline across the island of Ireland

"There was an implied wisdom at a time that suggested the local wildlife would adapt to the presence of a new species," he said.

"It's maybe too early to say if that is the case with mink."

The Irish Department of Housing, Local Government and Heritage said controlling mink numbers was "an ongoing issue".

• The invasive species causing concern across Ireland

• Seabirds return after mink 'eradication'

• Invasive species cost NI economy £46.5m each year

The American mink is one of 78 species included on the Republic of Ireland's list of invasive alien species - that means work is undertaken "to manage, control and, where practicable, eradicate these species".

"The National Parks and Wildlife Service prioritises the protection of nationally important ground-nesting bird sites and is also looking to expand these efforts to vulnerable sea-bird colonies," a spokesman for the department said.

He added: "Funding provided to local authorities in Ireland under the National Parks and Wildlife Service's Local Biodiversity Action Fund is also supporting mink control operations in some areas."

Earlier this year a member of the Irish parliament called for a more radical approach.

Fianna Fáil TD (Irish MP) for Tipperary Jackie Cahill wants a €20 (£17) bounty paid per tail to mink hunters.

A scheme offering €3 had been in place previously.

At that time junior agriculture minister Malcolm Noonan promised to examine the feasibility of reintroducing such a scheme.