European Mink

Mink are mainly nocturnal, emerging from their dens to feed at night on a diet of small animals including water vole, birds, frogs, molluscs, crabs, fish and insects (5). This range of prey, hunted in water, on land, in swamps and burrows is considerably greater than the range of more specialised mustelids like otters and weasels. This carries both costs and benefits, as a specialised hunter will be better adapted than a generalist at exploiting a certain prey, but a generalist, like the mink, has the advantage of being able to hunt different prey should one type become scarce (6). This mammal is a wanderer, occupying large home ranges (up to 15 km of river) and using rarely the same den. The female usually stays close to the den, unless a shortage of food drives it to find another location (2). They lead solitary lifestyles, except during the breeding season, from February to March (7), when they seek out mates using a repertoire of sounds from hisses and screams to chuckling calls. Males first seek out the females whose territories overlap their own, before searching further afield (6). Mating is often preceded by very aggressive encounters between the two sexes. The females' gestation period is between 5 – 10 weeks, the birth being in the spring when there is an abundance of food and shelter (2). The female will give birth to 2 – 7 young per litter and raises them alone in a den, suckling them for 5 – 6 weeks (4). Minks are born blind and helpless, and so depend on parental care until they are weaned at about 10 weeks, leaving the den after 12 – 18 weeks. They reach maturity after one year, and live for about 6 years in the wild and up to 12 years in captivity (2).

The range of threats, both commercial and ecological, facing this species, has significantly reduced the mink's population across Europe. In 1994 the IUCN upgraded the status of this species from Vulnerable to Endangered (1). In the early 1990s an international conservation program was set up by several partners across Europe (Ministry of the Environment, French Mammal Society, GREGE, ONC, University of Barcelona and Government of Catalonia) (8). The program's objective was to find priorities for a conservation plan by characterizing the bio-ecology of the species, analyzing causes for its decline and assessing the genetic variability of western populations. A rescue project has also been set up on an island in the Baltic, where the American species has been excluded, in an attempt to increase the European Mink's numbers in captivity (6). In France a national action plan for the conservation of the European mink was initiated by the Ministry of Environment (the first plan ran from 1999 to 2003) and has been coordinated by the SFEPM (French Mammal Society). A second plan will probably begin in 2006, but the SFEPM continues to work on some major activities in the conservation of the European mink (9).

The European mink is one of Europe's most endangered mammals. It is a medium sized mustelid with a long slender arched body, short legs and a short bushy tail (2). The fur is normally blackish brown with a distinctive small band of white fur around the upper and lower lips and occasionally on the throat (4). This marking and its smaller size usually distinguishes it from the American mink M. vision (5), but occasionally individuals may look so similar that only the skeleton or genetic analysis can guarantee correct identification (6). Its dense pelage is short, even in the winter (7), as it does have a thick water-repellent undercoat which insulates the mink when swimming (4). The European mink has other adaptations for a semi aquatic life; its feet are partly webbed and therefore useful for hunting underwater, swimming and diving (6). However, its eyesight is not well adapted to seeing underwater and so it relies heavily upon its sense of smell when foraging for terrestrial prey (6). Males and females look very similar, but the males are up to 80% larger (2). The reason for this difference is that males compete for mates and territories and so benefit from being larger, while the females have to protect and feed the offspring as well as themselves. If the females were larger they would have to consume even more food for themselves, which would result in spending less time with the young (6). Mink offspring are similar in appearance to adults (6).

Mink are semi-aquatic animals and inhabit densely shaded banks of lakeshores, rivers, streams and marshlands (6). They are rarely found more than 100 meters away from fresh water (7). One way to find Mink is to look for muskrat huts and burrows. If they are abandoned mink will simply move in, but they may also take over occupied huts, killing and eating inhabitants (2). Mink will also make dens in natural cavities in stream banks, under trees and in drift piles, lining them with grass, leaves, fur or feathers (7).

A century ago the European mink could be found throughout the European continent but its populations have severely declined and it is extinct or greatly reduced over most of its former range (6). It is known to survive only in small numbers in parts of Eastern Europe and some areas of Spain and France (5).

Classified as Endangered (EN A1ace) on the IUCN Red List 2004 (1), and listed on Appendix II of the Bern Convention (3).

Populations of the European mink have suffered from a series of ecological and commercial threats (4). Habitat loss is a serious threat to the mink in parts of Europe, where hydroelectric developments and water pollution have increased significantly over the past few decades (7). Another major reason for its decline is commercial trapping for fur (4), even though it is less valuable than the fur of the American mink M. vision (7). In addition, the introduction of this larger species in 1926 has created severe competition with the European mink for food and habitats, and has significantly reduced this native species' population (5). In France yet another threat comes from unintentional poisoning and trapping as a result of efforts to control coypu (Myocastor coypus) populations in the area. Pest control trapping and accidental mortality through vehicle collisions also affects populations in western areas of its range (1).