Erica von Essen
Ordinary place
The Stockholm archipelago, comprised of some 30,000 islands, contains residential homes, businesses, and infrastructure similar to other inhabited regions. Residents go about their daily lives, commuting to work or school, and engage in typical activities—they shop, they socialize, they spend times on outdoor recreation like hiking, ice-skating in winter, berry-picking in fall and swimming in summer. Heavily promoted for its unique nature, the archipelago, is a prime destination for foreign tourists. The Swedish tradition of everyman’s right (allemansrätten), or freedom to roam, means that most of the archipelago including its shores, are, at least in theory, accessible for all to visit and enjoy.
Capitalizing on its accessibility appeal, Stockholm County public transport system advertises that one can travel from the most inland/western parts of Stockholm to the outermost coast of the county’s archipelago on a single ticket or monthly card. In this way, it is seamlessly integrated in Stockholm’s city infrastructure. Yet the archipelago is also known for its natural beauty and species richness, including marine life and seabirds like the eider, guillemots and cormorant, along with various waterfowl and raptors. A number of nature reserves exist in a mosaic with residential properties.
Mobile Species
The North American mink has found a home across Sweden and in most of Europe. It particularly thrives in coastal and semiaquatic settings, where access to its prey foods is abundant. In the Stockholm archipelago, the mink has established reproducing populations since almost one hundred years back. The habitat offers plentiful rocky nooks for nesting bird populations and provides the mink with easy access to chicks and eggs, as well as a host of fish and amphibian species to balance its diet.
Mink are principally nocturnal animals, are excellent swimmers, and hunt with a combination of stalking, climbing, swimming and diving. They lead solitary lives in dens and burrows formed in natural crevices often along the rocky coast. They may make their presence known to other minks and animals by scent-marking through a musky anal odor, and to humans by sometimes raiding chicken coops in search for eggs, or undermining housing or landscaping structures by digging and denning around properties. For the most part, however, the minks are elusive and quick around humans, and few are able to distinguish this particular mink from other mustelids such as the rare European mink, or even sea otters.
Mink in the archipelago are curiously less shy and elusive than those at inland water bodies. This discovery reflect a recent trend among ecologists to examine e.g. urban and rural behavioral and phenotypical distinctions across species. One also distinguishes between males and females by the latter’s faster, smarter and more elusive movements. Mink are most mobile toward the end of summer when the pups leave the den and during mating season before when the males seek out females.
Biodiversity dilemma
Finding a litter of playful baby minks under your summer cabin, scurrying over your deck, can be a delight to many. Scoring high on the cuteness scale, the mink is a more aesthetic neighbor than rats, owing perhaps to its fluffy tail, round face, and shiny fur. Because it has been here since the 1930s or earlier, moreover, some might also maintain it has a right of domicile.
However, the mink is also a stone-cold killer, capable of taking out whole colonies of sea and coastal birds. They have particularly threatened the following endangered or rare species: Cepphys grylle, Melanitta fusca, Aythya fuligula, Stercorarius Parasiticus, Hydrocoloeus minutus, Sterna paradisea, Sterna hirundo and Sterna hirundo. Even removing a few individual minks from sensitive breeding areas can have significant impact on the recovery of these bird populations.
Removal of mink is carried out in several parts of Europe where they have established themselves, with leading projects from Finland where some 50,000 mink are culled each year (compared to 5000 in Sweden and Norway) (FAMNA, 2020). Volunteer-based hunter programs to trap or shoot a mink are a principal and cost-effective method of removal, since it is not feasible for state personnel to do all the work. Because mink are so well-provisioned with diet in their habitat, early attempts at devising traps with lures/baits of food (like blood, fresh fish, dried fish, shrimp, crab, bird) did not take. Instead, FAMNA devised a trap-and-lure combination that used mink hormone from their glands (used for scent marking), attracting their conspecifics, in a kill-trap (Trapper-90).
Actors & Players
The mink brings together both direct stakeholders who encounter it, and stakeholders who have an investment in the species or goods that the mink is seen to imperil. At present, the perhaps chief encounters of mink are the hunters tasked to cull it. Until now, mink culling has been coordinated jointly by Stockholms Skärgård, Upplandstiftelsen, relevant county administrative boards, and the collaborative Baltic-Nordic project FAMNA, which aimed to reduce mink in across the Nordic countries (2017-2020). A jurisdictional dilemma quickly emerged for mink cullers in the Stockholm archipelago: land in the archipelago was fragmented in ownership between private landowners whose contracts and leases took time and effort to track down (to ask for permission to remove mink); much of the land had a nature reservation designation to it, thus prohibiting hunting and requiring particular licenses for exemption, and the Swedish defence also owned land around the coast. Not only was it difficult to obtain permission to hunt on these lands, which could take time to process, but the camera-traps that hunters usually rely on to stay informed when mink had appeared, or been caught in a trap, were prohibited due to security concerns.
A key way forward has thus been to so far get private landowners to ‘do their part’ in mink culling. Everyone can legally put out a trap for mink, and are encouraged to do so. No special allowances or hunting licenses are required to do so. At present, it is estimated that some 70-80 percent of mink outtakes are during active hunting, with the rest through traps. Extrinsic motivation for mink culling exists in some parts of Europe in the form of bounties, but it has not yet been tried in Sweden. Were it to be enforced, people’s relationship to minks would likely change. For instance, in Norway, researchers discovered that incentives for culling mink were missing, and suggested instead awareness and recruitment campaigns appealing to hunters’ sense of responsibility for biodiversity and specifically by framing the mink as a threat to their harvestable species (Stien and Hausner, 2018).
The bird lobby, in particular, has been instrumental in appealing to the necessity of culling meso-predators like the mink. Hence, following the mink’s clear threat to many rare birds, many consider that it has outstayed its welcome.
Some attempts were made to utilise strategies from other parts of the world with a longer history of species trapping and eradication. Thus, FAMNA first used the New Zealand trap GoodNature18 (there used for rats and ermine), but without any success in the Swedish case, as the minks did not enter it. Today, apart from traps, a Nordic model of mink hunting typically involves a hunter entourage of several dogs to flush out mink, leaf-blowers, human interceptors in boats and a shooter. It is a more-than-human collaborative endeavour, which has also been criticized on animal welfare grounds. The mink’s classification as invasive species, however, makes it a relatively low priority to champion, as these unwelcome critters are generally non grata.
History
Mink were imported from North American in the 1920s, reaching Scandinavia as a first port before the rest of Europe. The purpose was fur farming. However, following escapes and releases, mink spread into the wild. In addition to negligence that enabled encaged mink to run away from capture, several actors seem to have been behind these “leaks,”. Well-covered cases include animal rights activists breaking their cages and freeing them. However, it is also likely that as for many other imported species, hunters introduced mink to the wild when possible, to supplement game species particularly in trying times like during World War II.
Interestingly, mink fur farms are still legal in Sweden. This may be something of an anachronism, especially as Denmark has closed such farms (partly due to corona) and because there is a strong animal rights sensibility in the Swedish public. The question of shutting down mink farming has been on the agenda in since the 1980s, but the urgency of question has since faded and not even the events in Denmark reanimated this debate. But the source contribution of minks from fur farms to nature is now negligible, as mink now have independently reproducing populations.
Efforts to control mink populations in the wild now go back decades. At the Stockholm archipelago site Stora Nassa, a Natura 2000 designation, mink culling has been underway systematically since 1993 with cooperation with the Swedish Hunting Association. As its populations dwindled on the island, several bird species came back including the Melanitta fusca.
Future
There is a stated goal across various municipalities to make the archipelago “living”, “sustainable”, “accessible” and conducive to recreational activities. In particular, there has been a focus on having more permanent, year-round residents. If this shift in demographics occurs, resultant shifts in attitudes toward the mink may also be forthcoming: from a cute summer guest to an everyday nuisance that undermines construction and causes unpalpable smells. In 2024, the SEPA appears to scale back slightly on its push to eradicate invasive alien species, such as the stone marten, at least in terms of providing funding for culling programs. This has not yet affected the mink but, the future of state funding for its culling remains somewhat uncertain.
FAMNA (2020) Riktlinjer för FAMNAs förvaltningsmodell i olika miljöer Reportno.
Stien J and Hausner VH (2018) Motivating and engaging volunteer hunters to control the invasive alien American mink Neovison vison in Norway. Oryx 52(1): 186-194.