Background The Western Isles of Scotland are of particularly high national and international nature conservation importance for their breeding populations of several species of wader and other water birds. Consequently, 5 SPAs covering almost 150 km² have been designated to protect the vast assemblages of breeding birds present in the islands Unfortunately, these extraordinary sites have been threatened by a relative newcomer to the area, the American mink (Mustela vison). Having escaped from mink farms in the late 1950s, this species soon established itself on the islands of Harris and Lewis. Here it has caused widespread breeding failure and losses of ground-nesting birds. The spread of mink into the more remote islands of North and South Uist and Benbecula has threatened the continued existence of many bird populations in key SPAs. The species that are most risk are Gavia stellata, Gavia arctica, Crex crex, Sterna albifrons, Sterna paradisaea, Sterna hirundo, Calidris alpina schinzii and Charadrius hiaticula. By 2000, it was estimated that there might be around 200-300 breeding female mink already present on the Uists and Benbecula. Urgent action was therefore needed to eradicate these individuals before they became too established and numerous. Objectives The overall objective of the project was to prevent significant disturbance and losses to internationally important ground-nesting populations of bird species - Annex 1 of the Birds Directive and regularly occurring migratory species - within SPAs. The project objectives are therefore: To protect vulnerable ground-nesting bird populations on North Uist, Benbecula and South Uist by the eradication of mink from these islands To reduce mink populations on South Harris to the extent that the risk of re-colonisation of North Uist is minimised, while plans are developed to address the management of the species elsewhere in the Western Isles To collect data on effective control methods. Mink populations at different starting densities and their responses to control upon which to made a model for assessing the costs of eradicating mink throughout the Western Isles To assess the effects of mink removal on the status of protected bird species To promote an awareness of bird conservation issues and the international importance of the Western Isles, including the risks posed by mink to island populations, and to disseminate the findings amongst other European countries facing similar problems.Results This LIFE project significantly reduced numbers of mink and therefore threats to internationally important ground-nesting bird populations. Its efforts in SPAs in the Western Isles of Scotland, UK demonstrate good practice for other regions affected by presence of American mink. The LIFE project carried out an extensive trapping programme to eradicate mink from the two Uists and Benbecula, and to significantly reduce their population on Harris. Humane trapping methods - used by two teams of six full-time trappers - trapped 532 mink –302 in Harris and 230 from the Uists. Project monitoring and the completion of a PhD study examined mink behaviour and the most effective and efficient methods for their humane elimination. The project tested techniques, including floating traps, roadside traps, traps left un-baited until mink were known to be present and the use of dogs. The project also tested methods of detecting mink presence from faecal material and from hair samples, although these proved to be very expensive. The result was a model of mink control - including costs - for the whole of the Western Isles. This was already used to guide the project’s trapping strategy and favoured: use of scent glands in all traps - three times more effective than fish bait use of collapsible traps to target areas where mink signs are found increased trapping intensity in rutting and dispersal seasons use of dogs to locate mink den sites - for subsequent trapping - in likely habitatsThe last mink caught in the Uists was recorded in March 2005, giving a high level of confidence that the programme eradicated mink from these islands. Mink numbers in Harris were substantially reduced - with trapping rates falling considerably. The project’s successes suggest for the first time that future eradication could be achieved on this island. Monitoring studies on the breeding of protected birds species have already provided encouraging results. In particular, studies of breeding arctic terns (Sterna paradisaea) showed that hatching success increased significantly where mink had been removed. Unfortunately, overall tern numbers did not yet see significant improvement due to other factors. Finally, the project received much local publicity and produced several scientific papers and presentations on its work. Local benefits to the economy were appreciated amongst fish and poultry farmers, for whom mink were also a significant pest.