The historic Inchcolm Island in the Firth of Forth is home to black rats, a survey has revealed.
The small island is one of Scotland’s historic jewels, drawing thousands of tourists every year to its 12th century Augustinian abbey. The island, east of the Forth Bridge, is also home to wartime coastal defences and wildlife including seabirds and seals.
The invasive rats were discovered in a survey by Bob Tevendale, Natural Heritage Advisor, Commercial and Tourism for Historic Environment Scotland (HES), who confirmed their presence using infrared cameras at night.
Inchcolm is thought to be among the last remaining island populations of black rats in the UK, after the Shiant Isles east of Lewis were declared free of the pests recently in a bid to protect its breeding seabirds.
It is thought the rats - which are smaller and less numerous than their more voracious brown cousins - may have been present on the island for many years but could pose a threat to its small puffin population.
Mr Tevendale said: “They are definitely black rats. Although I’m not sure of exact numbers it seems to be a small residual population. The main concern would be for the puffins that nest in burrows at the western end of the island.”
Inchcolm Island has played an important role in Scotland’s history. Supposedly visited by St Columba in 567, it was named after him in the 12th century when the abbey was established. The abbey is now among the best preserved groups of monastic buildings in Scotland. The island’s wartime defences formed part of the “middle line” of gun emplacements built to deal with German warships and the Luftwaffe.
Inchcolm is privately owned, although HES manages the area around the historic abbey and carries out pest control. Mr Tevendale added: “Black rats may be less destructive than brown rats, but when their preferred vegetarian diet is in short supply they can go after bird populations - which have risen on the Shiant Isles since the rats’ removal.”