Not the en­emy

You’ll have heard of the no­to­ri­ous Amer­i­can mink, dev­as­tat­ing our wa­ter voles, but what of the Euro­pean mink? This lit­tle-known an­i­mal is not a mon­ster – it’s prob­a­bly the con­ti­nent’s most en­dan­gered mam­mal, says Nick Fun­nell.

BBC Wildlife Magazine - - Contents - NICK FUN­NELL is a jour­nal­ist based in Madrid; www.nick­fun­

What makes Euro­pean mink dif­fer­ent to Amer­i­can mink?


As­mall head darts out of the den en­trance and sniffs the air. It van­ishes back in­side but re­turns sec­onds later, del­i­cate nose twitch­ing like crazy, shiny eyes peer­ing all round, choco­late-brown fur immaculate in the Span­ish sun­shine. The dusty route through the un­der­growth to the wa­ter ahead looks clear, but this wary crea­ture won’t dare move un­til she’s cer­tain.

This is Lluçanesa, a fe­male Euro­pean mink just over a year old. Her den is, sadly, not a cosy river­bank bur­row but a wooden nest­ing box laden with sen­sors at­tached to her en­clo­sure at the Fieb Foun­da­tion, a wildlife res­cue and re­search centre about 50km out­side Madrid, Spain.

It’s my first glimpse of one of th­ese shy, semi-aquatic mustelids – a rel­a­tive of the pole­cat and ot­ter – and it un­for­tu­nately has to be here be­cause you’re ex­tremely un­likely to spot Euro­pean mink in the wild. Not only do they pre­fer not to be seen, but they’re also among the con­ti­nent’s most threat­ened car­ni­vores and a strong con­tender for its rarest mam­mal.

Euro­pean mink once roamed the river­banks of much of con­ti­nen­tal Europe – though they were never UK na­tives – but are now rel­e­gated to a few iso­lated pock­ets in its far west and east. Fewer than 500 are thought to cling on in north­east Spain along the wa­ter­ways of the Ebro and Cantabrian basins, while the Danube Delta and Dni­ester River in Ro­ma­nia/Ukraine may be home to 1,000–1,500. Some are also likely re­main­ing in south-west France and Rus­sia, but ev­ery­where re­li­able fig­ures are lack­ing. In Spain the last – and so far only – na­tion­wide cen­sus dates from 2001.

The only thing we can be sure of is that the num­bers are de­creas­ing, and there is a real risk this Crit­i­cally En­dan­gered mam­mal could dis­ap­pear – pos­si­bly in as lit­tle as five years in western Europe, WWF Spain has warned. “I think this is the last mo­ment for the Euro­pean mink,” says Fieb di­rec­tor and wildlife vet Sil­via Villaverde.

If you’re sud­denly re­al­is­ing you don’t know much about Europe’s most-en­dan­gered car­ni­vore – don’t worry, you’re not alone. As a Brit who’s lived in Spain for the last decade, I’ve al­ways been im­pressed by the coun­try’s ef­forts to save the iconic Ibe­rian lynx, but the Euro­pean mink has never en­joyed the recog­ni­tion that would guar­an­tee the same stable sup­port to safe­guard its fu­ture.

Watch­ing th­ese cute slith­ers of brown fur scoot­ing among the veg­e­ta­tion and pools of their Fieb en­clo­sures, it’s hard to fathom why. Their char­ac­ters are an ir­re­sistible mix of sen­si­tive and psy­cho. “Com­pared with all the other species I’ve worked with, they’re the most del­i­cate,” says Villaverde, adding that it can nev­er­the­less take an hour to wran­gle fiery fe­males into a cage dur­ing breed­ing sea­son. “They’re small, but they’re lit­tle thugs.”

For most peo­ple, ‘mink’ con­jures up images of fur coats worn by Cruella de Vil types, and the fur trade is cer­tainly

partly re­spon­si­ble for the an­i­mals’ dis­ap­pear­ance. “The de­cline started at the end of the 18th cen­tury in cen­tral Europe,” ex­plains Madis Põ­dra, who with part­ner Asun Gómez leads the Euro­pean Com­mis­sion-backed Life Lutre­ola Spain project, the only ma­jor Euro­pean mink con­ser­va­tion pro­gramme in Spain.

“But mostly it’s be­cause of habi­tat de­struc­tion,” Põ­dra says. “The chan­nelling of rivers and more in­ten­sive agri­cul­tural work af­fected the fresh­wa­ter habi­tat. And the Euro­pean mink is quite sen­si­tive to that.” Then at the start of the 20th cen­tury the fur trade fur­ther has­tened the species’ de­cline. “In some years, 75,000 Euro­pean mink were killed in Rus­sia alone,” he says grimly.


To­day the fur trade is less of a prob­lem, but it has spawned an even big­ger threat: Amer­i­can mink. As in the UK, th­ese fur-farm es­capees are hav­ing a dev­as­tat­ing im­pact on the con­ti­nent’s wildlife, and the Euro­pean mink is right in the fir­ing line. Al­though the two species aren’t closely re­lated – the Euro­pean mink has more in com­mon with the pole­cat, with which it oc­ca­sion­ally in­ter­breeds – they in­habit the same eco­log­i­cal niche.

The big­ger, brasher Amer­i­cans mus­cle out their smaller Euro­pean cousins wher­ever the two come into con­tact. And, as Gómez’s re­search has found, that doesn’t mean sim­ply out­com­pet­ing them for re­sources, but di­rect vi­o­lent con­fronta­tions. “We have seen how Amer­i­can mink have killed Euro­pean mink.”

Euro­pean mink also have lower breed­ing suc­cess and need larger ter­ri­to­ries to sur­vive. Per­haps they are less

ef­fi­cient at hunt­ing the fish (mostly bar­bels, trout and min­nows), small mam­mals, cray­fish, rep­tiles, am­phib­ians and birds on which they de­pend. So they quickly lose out when the in­vaders ar­rive, dis­ap­pear­ing from the af­fected river within two to four years, says Põ­dra.

It’s no sur­prise that from their base in Haro, in the heart of the Rioja wine re­gion, Gómez and Põ­dra are de­vot­ing most of Life Lutre­ola Spain’s re­sources to erad­i­cat­ing the Amer­i­can mink. And they have a highly ef­fec­tive weapon: the mink raft. Since 2015, they and their team of 200 tech­ni­cians and rangers have cleared Amer­i­can mink from a 400km-stretch of the River Ebro and its trib­u­taries, and their fleet of 1,000 rafts con­tin­ues to ‘clean up’ other wa­ter­ways in the Basque Coun­try, La Rioja, Aragón and Va­len­cia re­gions.

Four hun­dred kilo­me­tres away at the Fieb Foun­da­tion, I watch the com­ings and go­ings of Lluçanesa and the cap­tive-breed­ing centre’s cur­rent pop­u­la­tion of 15 other Euro­pean mink on a bank of mon­i­tors wor­thy of BBC Two’s Spring­watch studio. In ad­di­tion, there is another ma­jor fa­cil­ity in Lleida, Cat­alo­nia, and a smaller centre in the Basque Coun­try. To­gether, they house 50 or so mink.

A host of cam­eras and sen­sors in­stalled in their 35–110m2 en­clo­sures mon­i­tor the mink round the clock. The aim is not sim­ply to keep them safe, but also to col­lect valu­able data. Since the Fieb Foun­da­tion started work­ing with mink in 2013, it has tested scales and ra­dio-fre­quency iden­ti­fi­ca­tion sys­tems in the nest­ing boxes that de­tect how of­ten the an­i­mals go in and out, as well as ceil­ing­mounted 360° cam­eras – nor­mally used to track hu­mans in pub­lic spa­ces – to ob­serve their be­hav­iour.


This cli­mate of in­no­va­tion has helped the foun­da­tion find in­ge­nious so­lu­tions to the prob­lems as­so­ci­ated with breed­ing Euro­pean mink in cap­tiv­ity. Cap­tive-born males, for in­stance, are less likely to ex­hibit mat­ing be­hav­iour than those brought in from the wild – nor­mally you would ex­pect it to be the other way round. To coun­ter­act this, the team has been en­cour­ag­ing the preda­tory in­stincts of the mink by in­tro­duc­ing live prey in the form of mice trained to flee from their scent. . Soon tench will be of­fered too.

The centre has s just en­joyed its most suc­cess­ful year yet. Of the 16 adult mink liv­ing here in 2017 (eight males and eight fe­males), five males ex­hib­ited mat­ing be­hav­iour ur and five fe­males be­came preg­nant. In all, 12 kits were born: dou­ble the 2016 to­tal.

And there’s a back-up plan. The he Fieb team is talk­ing king to re­searchers in n the USA to adapt pt


pi­o­neer­ing tech­niques that res­cued the En­dan­gered black­footed fer­ret, which very nearly went ex­tinct in the Midwest prairies. Just 18 fer­rets were left by the mid-1980s, so th­ese charis­matic lit­tle car­ni­vores suf­fered a ‘ge­netic bot­tle­neck’ where in­breed­ing caused by chronic lack of ge­netic diver­sity threat­ened the vi­a­bil­ity of the en­tire species. By tak­ing all of the sur­viv­ing fer­rets into cap­tiv­ity to man­age the pop­u­la­tion ar­ti­fi­cially, the species was saved at the eleventh hour. Tar­geted re­leases of care­fully se­lected cap­tive-bred fer­rets fol­lowed.

Ly­ing 20km off the coast of Es­to­nia in the Baltic Sea, Hi­iu­maa Is­land was his­tor­i­cally never home to Euro­pean mink. But af­ter the last wild in­di­vid­ual in Es­to­nia was cap­tured in 1996, the 1,000km2 is­land’s dis­tance from the main­land – and thus from ma­raud­ing Amer­i­can mink – made it per­fect for a sim­i­lar rein­tro­duc­tion project. Ev­ery year be­tween 2000 and 2016, cap­tive-bred Euro­pean mink were re­leased on the is­land. To­day, the pop­u­la­tion has reached about 100 and so the rein­tro­duc­tions have stopped.


Now Põ­dra, an Es­to­nian, is hop­ing that his ex­pe­ri­ence on Hi­iu­maa Is­land will lead to sim­i­lar suc­cess in Spain. Life Lutre­ola re­leased its first cap­tive-bred Euro­pean mink into the wild at two sites dur­ing Au­gust and Septem­ber 2017. Eight mink were set free to re­in­force an ex­ist­ing pop­u­la­tion on the Leizarán River in Gipuzkoa prov­ince in the Basque Coun­try, while 11 more were re­leased to build a new pop­u­la­tion on a 150km stretch of the River Aragón, where sur­round­ing moun­tains and a dam have so far kept Amer­i­can mink out.

Only the least ge­net­i­cally valu­able an­i­mals are picked for re­lease. Suc­cess will take years, so keep­ing the cap­tive pop­u­la­tion healthy is para­mount. “An­i­mals with genes that are less rep­re­sented in the pop­u­la­tion will stay in cap­tiv­ity to main­tain diver­sity,” Põ­dra ex­plains. Since Spain’s

Euro­pean mink pop­u­la­tion has par­tic­u­larly low ge­netic diver­sity, the plan is to start mix­ing it with the 250 or so in­di­vid­u­als in the 25-year-old cap­tive-breed­ing pro­gramme in Es­to­nia. This will cre­ate a sin­gle cap­tive pop­u­la­tion big enough to main­tain diver­sity. “The Span­ish and Es­to­nian mink are not that dif­fer­ent,” Põ­dra says. “Ge­netic stud­ies show that the sep­a­ra­tion oc­curred quite re­cently.”

Fol­low­ing their re­lease this sum­mer, the 19 Euro­pean mink are be­ing ra­dio-tracked to check their progress. En­sur­ing their sur­vival means also keep­ing tabs on the ad­vance of Amer­i­can mink, so Gómez and Põ­dra are aim­ing to un­der­take a new cen­sus of both mink species in Spain. But with the Life Lutre­ola scheme due to end in 2018, con­cerns re­main over what hap­pens next.

Hope is on the hori­zon at last, af­ter the Span­ish En­vi­ron­ment Min­istry de­cided in July 2017 to cat­e­gorise the Euro­pean mink as a species in a “crit­i­cal sit­u­a­tion”, fol­low­ing a WWF cam­paign and an IUCN open let­ter. WWF Spain is op­ti­mistic that the new sta­tus will pave the way for the gov­ern­ment to pro­vide re­sources for a more com­pre­hen­sive emer­gency plan. But it also wants bet­ter co­or­di­na­tion among the re­gional, cen­tral and Euro­pean ad­min­is­tra­tions.

Un­til such a plan is in place, those fight­ing to save mink have no op­tion but to go on us­ing what­ever re­sources they can find to safe­guard the species. The al­ter­na­tive is un­think­able. “Rivers have al­ways been part of our lives, and you can’t con­ceive of rivers with­out Euro­pean mink,” says Põ­dra. “Once the mink go, it’s like the river isn’t the same any more.”

Money and sup­port will only be forthcomin­g if more of us un­der­stand the Euro­pean mink’s plight. So tell the world. If ever you find your­self dis­cussing the Amer­i­can mink, make sure you also re­mind peo­ple about its smaller, more vul­ner­a­ble Euro­pean cousin that’s in des­per­ate need of help.


Above: Euro­pean mink favour densely veg­e­tated river­banks. Below: the Fieb Foun­da­tion is breed­ing mink in cap­tiv­ity to boost wild pop­u­la­tions.

Life Lutre­ola Spain re­leased its first cap­tive-bred Euro­pean mink into the wild in 2017. The River Aragón was one of the re­lease sites.

Euro­pean mink usu­ally have lit­ters of three to five young – fewer than Amer­i­can mink.

At the Fieb Foun­da­tion mink use wooden nest­ing boxes at­tached with sen­sors that mon­i­tor the mustelids.

A fe­male for­ages at the shore of a small pond. Euro­pean mink hunt a range of prey, in­clud­ing small mam­mals, fish, birds and am­phib­ians.

Above: a fe­male peers through the un­der­growth. Below: Madis Põ­dra ra­dio-tracks mink along the River Aragón.

Above: a Euro­pean mink shakes off wa­ter af­ter hunt­ing in a for­est stream.

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