Sometime during the 18th century, a shipwreck in the Minch waterway (which separates the Inner and Outer Hebrides) saw the arrival of a number of unwelcome visitors to the tiny Shiant Isles: invasive black rats. Finding food wasn’t a problem for these rodents, since the eggs and chicks of ground-dwelling land birds made for easy meals. Thus the population flourished. A survey in 2012 concluded there to be as many as 3,600 rats inhabiting the islands.
The Shiant Isles – whose name derives from Gaelic to mean ‘enchanted isles’ – are one of Europe’s most important seabird breeding sites, hosting up to 100,000 pairs of nesting seabirds each year. The predatory instincts of the rats made for bad news for this native birdlife, turning the islands into difficult breeding grounds for species such as puffins and razorbills, and essentially impossible ones for storm petrels and Manx shearwaters.
In 2014, RSPB Scotland, in conjunction with Scottish Natural Heritage and long-term custodians, the Nicolson family, embarked on an ambitious mission: to eradicate rats from the Shiant Isles.
The Shiant Isles Recovery Project followed in the footsteps of other regional rat-eradication schemes, such as on the islands of Ailsa Craig, Ramsey and Lundy, as well as those initiated around the world (including in South Georgia and New Zealand). The team set poisoned baits around the island’s rugged terrain during storm-heavy winter periods, when rat populations were traditionally at their lowest, luring the rodents with such flavours as cocoa and peanut butter.
Since 2016, regular monitoring has turned up no live rats on the Shiant Isles, the two-year window after which islands can be declared ‘rat free’. The sight of storm petrels nesting on the islands for the first time last summer strongly indicates that the rats have been completely eradicated.
‘This is an absolutely fantastic moment for the Shiant Isles and everyone involved in the project is delighted that they are now officially rat-free,’ says Dr Charlie Main, Senior Project Manager. ‘With so many of Scotland’s seabird populations in decline it’s vital that we do all we can to help them. Making these islands a secure place for them to breed is really important.
‘Over the next few years we’re really looking forward to seeing the full impact of the islands’ restoration flourish with the seabirds enjoying improved breeding successes, and other species beginning to breed there as well. We’ll also continue to work with the local community to ensure this special place remains free of rats. This project has paved the way for more island restorations to take place around Scotland and give our threatened seabirds the best possible chance for the future.’
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