Why is it that Skomer Island thrives with seabirds, whilst nearby Ramsey Island is comparatively empty? Jack Ashton explains why, and discusses the optimism for the future of Ramsey Island.

Just off the coast of Pembrokeshire, Wales, lie two islands. They are largely the same geographically, but have one devastating difference in their history: Ramsey Island was invaded by rats, whereas Skomer Island wasn’t.

On first glance, these two islands are almost identical; similar size, similar height above sea level, similar terrain. But on closer inspection, Skomer is a thriving metropolis of seabirds – around 316,000 Manx shearwaters nest on the island, along with 22,000 puffins and many others, including guillemots and kittiwakes. Ramsey, on the other hand, is deserted in comparison. But this has not always been the case. Let’s go back in time to the late 1800s when Ramsey Island would have been a picturesque scene, much the same as Skomer is to this day.

Both islands were once a scene of beauty, rugged cliffs protruding from the Irish Sea with hundreds of thousands of seabirds swooping to catch fish. They were filled with nesting burrows reserved for either puffins or Manx shearwaters, whilst guillemots and other species would nest on rocky outcrops. The reason that they could be a seabird have was that both islands were free from terrestrial predators, such as snakes, or rats. However, things then started to change; rats invaded Ramsey Island, arriving from boats that crashed into the island. For the next century, these invasive rats ravaged the seabird population on Ramsey by eating their eggs and young. This saw the island’s seabird population deplete massively which is why, by 1999, puffins had become extinct on the island, storm petrels probably had as well, and the population of Manx shearwater dwindled. By 1999, it was decided that things had to change; RSPB volunteers teamed up with a team of experts from New Zealand company, Wildlife Management International, to attempt a total rat eradication.

By the year 2000, this eradication was successful! The invasive rats had gone, so for the first time in over 100 years, Ramsey Island experienced a period of calm. It was allowed to recover from the damage that these invasive predators had caused. I feel it is necessary to mention here that rats are not a ‘bad’ species. They go about their day-to-day lives as they always have; it is the fault of humans that they reached Ramsey. Islands are special and display some extremely unique ecosystems, and this is often due to a lack of terrestrial predators. Once predators are introduced, it skews the balance of life and can lead to detrimental consequences, as seen on Ramsey. Once this eradication was successful and Ramsey had time to recover, however, its seabird population had a prime opportunity to bounce back. For the first time since rats invaded, this island could start to look like Skomer once again; packed with puffins, full of fulmars and saturated with shearwaters.

Skipping ahead to today, Skomer and Ramsey island are bio-secure. In this case, it mostly means that efforts are taken to prevent the introduction of harmful organisms to the island (these include checking your bags for rodents, taking home your rubbish and packing food on the day you travel). By ensuring that terrestrial predators do not re-invade, seabirds are starting to recolonise. The population of Manx shearwater has increased around five-fold since the eradication, and storm petrels have returned to the island. Puffins, however, remain elusive; none have colonised yet. This is the ultimate goal, so puffin decoys have been deployed around the island to entice them back in.

Throughout Ramsey Island’s recovery, Skomer Island has remained a seabird stronghold; for example, it is thought that around half of the world’s Manx shearwaters live on this tiny island. It is an extremely special location, and one that requires equally as special care. It is the hope that, eventually, Ramsey Island will once again become as saturated with life as Skomer. This dream is not impossible. It is a perfect example of how we can learn lessons from the past, to improve the world for tomorrow. I hope that, in a couple of decades time, Ramsey Island will be able to match Skomer Island’s life once again, and we will be able to wander through thousands of seabirds flying overhead.

Invasion! The Contrasting Stories of Two Islands

Why is it that Skomer Island thrives with seabirds, whilst nearby Ramsey Island is comparatively empty? Jack Ashton explains why, and discusses the optimism for the future of Ramsey Island.