Pine martens could be used to help drive out invasive grey squirrels and help protect their native red cousins, experts will hear, as a result of research carried out at Aberdeen University.

The work, by Emma Sheehy at Aberdeen's school of biological sciences, was carried out in Ireland where a growing pine marten population has coincided with a decline in the population of grey squirrels and increasing numbers of reds.

Pine martens are native to Scotland and so could offer a new approach to controlling grey squirrels, which were introduced from North America in the late 19th Century to add variety to parks. However they reproduced rapidly and crowded out the red squirrel.

Loading article content

The red squirrel was dubbed the 'tufted acrobat' in a recent Scottish Natural Heritage poll which placed it Scotland's most popular mammal, second only to the golden eagle in a survey of popular wildlife. Its decline has also been attributed to squirrel pox and other diseases transmitted by grey squirrels. There are now thought to be in excess of 10 million grey squirrels in the UK and only 150,000 reds, mostly living in rural Scotland and Wales.

Using pine martens to help control grey squirrels will be one of the topics on the agenda at the Country Land and And Business Association (CLAs) scientific conference next month, based partly on Ms Sheehy's research. CLA members are keen to prevent the damage greys do to woodland and have been frustrated by restrictions on the use of warfarin-laced bait to control their spread.

Pine martens, a member of the weasel family, were themselves in decline, but have seen a resurgence an especially in Ireland where they were protected in the 1970s.

"Since then they have expanded considerably, moving back into the midlands of Ireland," Sheehy said. "AS they have repopulated central Ireland, the grey squirrel population has declined and the reds have come back.

"Our hypothesis is that pine martens drive out the greys - so as the martens get more abundant the grey squirrel population declines.

"We don't know if this is due to the martens eating grey squirrels or just scaring them away, but it points to a new solution for protecting red squirrels."

Sheehy is now turning her attention to Loch Lomond and the Trossachs and also studying the resurgence of pine martens in the Scottish Borders.

However she said that any initiative to encourage marten populations would take time to have a major impact on grey squirrel numbers. "For now we still need traditional tactics like trapping and shooting," she said.