Hebridean mink eradication project enters last year

Arctic tern colonies on the Hebrides will benefit from mink eradication. Credit SNH

April 2010. An ambitious mink project which covers 305,000 hectares and is the largest single species eradication ever attempted is now entering its final year of trapping. The Hebridean Mink Project (HMP) started in 2001 and has undergone two separate phases in combination with considerable effort by trappers and management teams.

1764 mink caught so far
Phase one caught 532 mink throughout the Uists and South Harris. And the current second phase, striving towards the ultimate aim of total eradication from the Outer Hebrides archipelago, has so far resulted in 1232 mink.

The distances involved are significant when placed in a national context; 3,297 km of coastline, 4,721km of freshwater loch edge and 1,831km of river and stream. This equates to 20%, 25% and 3% respectively of Scotland's potential mink habitat.

10,000 traps
In order to achieve this, more than 10,000 trap positions have been utilised in order to target every potential mink territory. All cage traps are opened on a rotational basis and when open are checked daily.

Iain Macleod, the mink project manager, said: "From the very start of the project we have been learning lessons; there is no manual for what we are trying to achieve, and the sheer hard work of the trappers is what makes this even possible."

Mink cause serious damage to birds and fish
Non-native American mink is a highly adaptable semi-aquatic carnivore which has been causing significant damage to ground nesting bird species, especially seabird colonies, and freshwater fisheries throughout Scotland.

Several areas of Lewis and Harris have for the first time produced no mink after a sequence of trapping, indicating that the population has locally been removed. This includes the area of East Loch Tarbert and Scalpay - previously one of the highest mink densities found anywhere in the Outer Hebrides.

"The efforts of the trappers are really starting to pay dividends and it is now up to the entire team to use the available population science and follow our strategies through in those areas were mink still persist," Iain continued.

Ground-nesting birds recovering
"Ground-nesting bird numbers appear to be recovering and in the case of the terns of Lewis and Harris they showed a significant improvement, not only in their productivity last year but also their geographical distribution. Whilst it cannot be claimed this is wholly due to the mink project, the removal of a significant predator must be a contributing factor."

North Uist
As part of the continuous monitoring work eight mink have been caught in an area in the north of North Uist. This brings the total number of mink caught in the Uists since the start of phase two to 26. This includes those caught on some isolated offshore islands such as Boreray and Hermetray.

And Iain added: "We continue to face challenges on an almost daily basis and the fact that our continued monitoring work in the Uists has discovered isolated satellite populations is one more which we will need to manage and develop a strategy for during the next year.

Please report mink sightings
"I cannot stress enough the importance of mink sightings being reported. We have always relied on the local populace of the Outer Hebrides to report sightings as soon as they are seen so that we can react to them quickly, before the animal leaves the area. In addition, those wishing to volunteer are always welcome and if individuals would like to contact the project, arrangements can be put in place.

"Whilst disappointing to discover that a relatively small number of mink have re-established in North Uist, it is not unusual for eradication schemes to face these setbacks. Everyone involved with the project is committed to eradicating mink from the entire archipelago and we will use all our available resources to try and achieve this goal in the year we have left."

Martin Scott, RSPB Scotland conservation officer in the Western Isles, said: "When people introduce mammal predators to islands where they don't naturally occur, wildlife nearly always suffers serious and challenging problems. The Hebridean Mink Project tackles such problems, and we wish the workers and volunteers success."

Mink colonisation
"The re-discovery of mink on the Uists demonstrates the importance of seeing such projects through to completion. We believe that with the right support and management this can be achieved in the Western Isles, benefiting wildlife, creating jobs and supporting poultry, angling and fish farm businesses. RSPB Scotland will continue to support the project by monitoring and reporting the responses of wild bird populations."

Mink first found their way into the islands' environment in the 1960s and 70s as escapees from fur farms and flourished in the abundant suitable habitat available in the Outer Hebrides.

Bird species which have suffered include Arctic tern, common tern, little tern, black throated diver, red throated diver, corncrake, dunlin and ringed plover.