Background The European mink (Mustela lutreola) is amongst the most critically endangered mammal species in Europe. Once upon a time it used to inhabit large parts of Central and Western Europe but populations began to crash at the beginning of the 20th century. Now the only viable population is to be found in Spain, with some small fragmented populations scattered around France and some areas in eastern Europe. The main reason for the drastic decline is competition from other mustelid species, primarily the American mink (Mustela vison), an exotic species which managed to populate the European continent after it escaped or was released from fur farms. Considering the precarious situation for the species, Tallinn Zoo initiated, in 1983, a captive breeding programme for the European mink, within the framework of an IUCN species specialist group. At present, the captive breeding stock numbers around 100 individuals. A trial release programme at Hiiumaa Island in western Estonia was started up in 2000. Objectives Building on the experience already gained with this species, the LIFE project intended to launch a more substantial release programme on the island of Saaremaa in western Estonia. First, the captive breeding facility would have to be enhanced to accommodate a maximum of 145 animals. This would make it possible to secure a captive population of satisfactory genetic constitution over a 25-year period, as well as to breed animals for release into the wild. 30-50 animals would then be released on Saaremaa in order to try to establish a wild population of European mink. This would be preceded by detailed field studies, removal of American mink and preparation of the animals for release. The dispersal and survival of around 20 of the released animals would be monitored by radio-tracking. The release programme already initiated at Hiiumaa Island was to be followed up by the preparation of a management plan for the population on this island. Core areas and habitats of both islands were to be protected by the end of the project. Results The two main parts of the project were to reinforce the size and genetic status of the captive population of Mustela lutreola (European mink) at Tallinn Zoo, and to establish a free-living population on Saaremaa Island. The project was successfully completed in so far as that the targets with reference to the size of the captive population and the number of released animals were achieved. It was however over-optimistic that success in terms of the size and genetic pool of the wild population could be obtained within a short timeframe. One of the lessons learned was that success can only be expected with a long-term effort, maybe ten years, considering the low recruitment rate in the released population. This effort will continue after the end of the LIFE project. THE RELEASE PROGRAMME: During the implementation of the project, it was decided to shift the release of animals into the wild from Saaremaa Island to Hiiumaa Island to reinforce the already existing introduced population there. By the end of the project in November 2004, 149 animals had been released, i.e. more than the number foreseen at project start, and the free-living population was estimated to be 16-28 animals. However, the overall objective to establish, during the project, a free-living and sustainable wild population of the target species on Hiiumaa Island, was not achieved. Low recruitment by the wild population seems to be the main concern for future management. The discovery that this may be linked to inability by many of the released males to contribute to reproduction, due to behavioural constraints (abnormal aggression) rather than physiological incapacity (such as sperm quality), is considered a very important outcome of the project, though more research will be needed to gain full scientific evidence. THE CAPTIVE STOCK AT TALLINN ZOO: This stood at 104 animals at the end of the project, e.g. very close to the target of 110 animals. In actual fact, numbers fluctuate between 95 and 160 animals, depending on the time of the year (release dates!). New breeding facilities and outdoor training enclosures were installed, and at the end of project, the beneficiary judged that the installations at Tallinn Zoo were the best conservation breeding facility for the target species in Europe, largely thanks to the investments done by the LIFE project. However, in order to assure the long-term sustainability with reference to genetic diversity, new wild-caught founders must be added to the captive breeding population and the problem with behavioural abnormalities and low reproduction by males born in captivity must be solved. From the start, it was obvious that this was a "high-risk-project", but also that it involved some of the only possible actions left to give the long-term survival of the European mink a chance and to create options for the restoration of viable free-living populations in the future. Even if it were to fail due to the many elements of uncertainty, there was a potential to gain valuable experience for the future. From that perspective, the project delivered according to expectations. NATURA 2000 AND THE DESIGNATION OF SITES FOR THE EUROPEAN MINK IN ESTONIA: On request from the Estonian Ministry of the Environment, the beneficiary presented a proposal for 10 core sites for the European mink on Hiiumaa Island, i.e. the project had a clear incentive impact on the Natura 2000 process in Estonia, with reference to the proposal of pSCI sites for the target species. A GENERAL AND IMPORTANT EXPERIENCE FROM THE PROJECT WAS THAT THE ESTABLISHMENT OF A FREE-LIVING POPULATION IS A MUCH LONGER PROCESS THAN ASSUMED WHEN PREPARING THE PROJECT: · "Soft" release methods, i.e. training the animals before release and giving support (shelters etc) after release, is more effective than "hard" release techniques of letting animals go without any training or support; i.e. the time and cost involved in training is justifiable. It is however still not possible to recommend which of the various combinations of "soft" techniques tested in the project provide optimal results. · Preliminary results from the monitoring indicate that there is no difference in survival between females released when pregnant or non-pregnant, although there is still too little data on the survival of the litters. · For the long-term management of the captive stock at various breeding centres in Europe, the current estimate is that a total 500 animals are needed in order to maintain 90 % of the initial genetic heterozygosity over 100 years. ATTITUDES AMONG THE LOCAL COMMUNITY: In 2003-2004, the beneficiary did a survey of general knowledge about the European mink project on Hiiumaa Island. 260 questionnaires were distributed, and 164 (64 %) were returned. The result can be briefly summarised: · 97 % knew about the project. · Most respondents knew about the rareness of Mustela lutreola and had a clear understanding that the species is a natural component of the boreal ecosystem. · 32-50 % (depending on stakeholder group) argued that existing restrictions for the benefit of the European mink are enough. · There were remarkable differences in attitude between age groups (22-45 years and 46-82 years): the older group being more afraid of the negative impact of the release of Mustela lutreola on fish and crayfish stocks, killing of hens etc. The older group also had an overall less good knowledge of the target species and resisted any new restrictions for the survival of the species. · Personal contacts were the most important "tool" for information and promotion. Second most important was local newspapers, radio and TV. The project website was primarily used by those who had a deeper interest in the subject.