Minks' high jinks make them not so super furry animals

Sat, Jan 21, 2012, 00:00

ANOTHER LIFE:OF ALL THE FURRY ANIMALS brought to Ireland by humankind, Mustela vison, the American mink must be the most widely regretted. Escaping from fur farms since the mid-20th century (or, as in 2010, the “liberation” of 5,000 mink into the wild), this versatile predator has bred and spread virtually to the whole of Ireland. Its capacity for overkill now extends even to the major seabird islands off our Atlantic coasts.

This month’s launch of a year-long bounty hunt – €3 for each furry tail – only brings home the sheer impossibility of freeing Ireland from the alien mink, except at impossible cost. A review for the National Parks and Wildlife Service has estimated that trapping 75 per cent of mink annually in a catchment of 800sq km over five years would cost more than €1.3 million. That was roughly the cost to Scotland of clearing mink from the Outer Hebrides, prime habitat for ground-nesting terns and waders.

In the first Irish study, about 20 years ago, Dr Chris Smal saw the mink taking “its place alongside the country’s native predators” and producing “a new balance” of local wildlife. Except for control where this balance was unacceptable, he concluded, “mink are best left to regulate their own numbers.” However, without the range of competitive predators that it faces in continental Europe the American mink in Ireland could expand to unusual densities – more than 30,000 individuals is one estimate. Eastern counties have the most mink now, but the west has the most attractive watery habitats, rich in vulnerable wildlife.

The new “balance” is already unacceptable. Local disappearances of waterbirds – moorhens, coots, mallard duck – have sadly impoverished much of the ordinary countryside. Anglers and shooters resent the competition for their quarry, especially when they have raised stocks of trout and game themselves. Farmers have horror stories of poultry wipeouts (“All my ducks!”).

Beyond this, however, lies the crucial ecological damage peculiar to the mink’s evolution. Competition underwater from the otter, its larger, faster cousin in the mustelid family, has forced it to prey on birds, most easily where they breed and with a “surplus killing” impulse exceeding even that of the fox. This is perfectly natural behaviour, possibly relating to orgins in Canada, where the storing of food against winter can have a more obvious point.

In Iceland, with similar problems, about 700 eider ducklings were found cached in one mink den. In the Hebrides, one mink wiped out a whole colony of nesting terns in a single night. A few kilometres north of me in Co Mayo, a little island in a coastal lake used to be crowded in summer with nesting sandwich terns. Since the first mink was sighted on the shore, about a decade ago, they have all disappeared.

Elsewhere on our western lakes, colonies of breeding gulls have met a similar fate. The threat to rarer bird species in protected areas (corncrakes, red-throated divers and grey partridge, along with waders and terns) has committed the National Parks and Wildlife Service to long-term trapping and eradication in Cos Donegal and Mayo and along the Shannon, often with the help of volunteers and farmers. Many of the projects are seasonal, using baited traps to clear a protected area before nesting begins in spring.

Ireland’s mink swim very well in the sea, recolonising offshore islands with surprising resilience. The record swim for the species stands at about 14km, which puts our most precious bird islands well within reach. Nesting on cliff ledges is relatively safe, but puffins, petrels and Manx shearwaters nest in burrows under turf and sea pinks. The first records and signs of mink have reached Co Clare’s protected Puffin Island and the Great Blasket, off Co Kerry, prompting this year’s Heritage Council grant to a BirdWatch Ireland team of researchers.

This may also have moved Minister for Heritage Jimmy Deenihan to initiate the €20,000 grant to the National Association of Regional Gun Clubs to support its €3-a-tail bounty scheme, running to the end of the year. “Historically, bounty schemes do not work,” concluded the scientists who prepared the National Parks and Wildlife Service review. Iceland, for example has had a long-term bounty scheme, but mink populations have continued to grow.

Deenihan’s one-off grant could seem necessarily modest but reflects, I’m told, a strong personal concern, especially for more trapping in the west. Meanwhile, six mink farms continue to operate in the Republic (one of them at Waterville, in Co Kerry) under licences from the Department of Agriculture. Minister for Agriculture Simon Coveney has asked a fur-farming review group to comment on the sector’s economic worth and the standard of the animals’ welfare until their final gassing.

So long as mink farms continue, concluded the National Parks and Wildlife Service report, there will be more escapes and wildlife damage. Indeed, the long-term costs of control could balance compensation involved in farm closure – an outcome devoutly to be wished, not least for the innocent, unmalicious but deadly efficient mink themselves.

Eye on nature

A male sparrowhawk that kept attacking my aviary attracted seven magpies to the surrounding trees. They created quite a chatter, which eventually drove him off, and then they dispersed.

Derek Pullen, Bray, Co Wicklow

We have a jay at our bird table for the past few weeks. He fills himself with peanuts, then fills his beak and flies off to his store.

Barry and Kathleen Sullivan, Castletownbere, Co Kerry

I found what looked like a 10in or 12in black snake-like slug or worm on top of my car. It had a pale belly but no feet.

Lynn Osborne, Galway

It was a slow-worm, a legless lizard, not native to this country but introduced to the east Burren.

I found a spider in the back garden. The closest match I found online was a false widow spider.

Caroline Mion, Killiney, Co Dublin

Yes, from the photograph you sent it was one of the false widows, Steatoda bipunctata, and belongs to the same family as the black widow but is not nearly as poisonous.

On December 30th, Jenny Seawright of Macroom, Co Cork, spotted frogspawn in her pond. And on January 6th, Sandra Landers of Ventry, Co Kerry, had two frogs cavorting in her pond.

Michael Viney welcomes observations at Thallabawn, Carrowniskey PO, Westport, Co Mayo, or email viney@anu.ie. Please include a postal address

In Iceland about 700 ducklings were found cached in one mink den. In the Hebrides, one mink wiped out a whole colony of nesting terns in a night