The dramatic sea cliffs, crags and stacks of Rathlin Island, county Antrim, rise more than 200 metres above the Atlantic Ocean and host one of the UK’s largest seabird colonies, including hundreds of endangered puffins, attracting up to 20,000 birders and tourists a year.

On a spectacularly sunny day in September, the cliff faces are devoid of birds, with the puffins already having made their annual migration to spend the winter months at sea. Instead, Rathlin’s cliffs are dotted with roped-up figures in harnesses and bulging rucksacks, directed from above by a Scottish mountaineer, via a walkie-talkie.

They are part of a crack team of 40 scientists, researchers, conservationists and volunteers who this week will put the first poisoned food into the bait stations designed to kill the island’s rats. It is the final phase in a £4.5m project to eradicate the key predators believed to be affecting the island’s puffin colony. Ferrets were eradicated in the first phase and it has been a year since the last confirmed sighting. Puffin numbers declined here by 74% between 1991 and 2021, according to an EU study.