Scilly’s Seabirds in Trouble: What the Latest Survey Found and How You Can Help
Scilly has lost almost half its seabirds in 30 years, yet Manx shearwaters have doubled where rats were removed. Here is what the latest survey found and how visitors and islanders can help.
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Puffins on the Western Rocks, shearwaters rafting at dusk and shags standing guard on every ledge. Seabirds are a big part of what makes the Isles of Scilly special. The latest full survey shows many of them are in serious trouble, but it also shows there is a proven way to bring them back.
This guide explains what the survey found, which species are struggling and which are thriving. It also covers the plans to protect seabird islands in the years ahead, and the simple things visitors and islanders can do to help.
Key Takeaways
- Scilly's seabirds fell by nearly 20% in eight years, and the islands have lost almost half their seabirds in 30 years.
- Gulls and shags have fallen sharply, common terns no longer breed every year and kittiwakes may soon be lost.
- Where rats were removed, Manx shearwaters doubled and storm petrels returned.
- Conservationists want to remove rats from more islands and keep them out with strong biosecurity.
- Visitors can help by keeping dogs on leads, using accredited boat trips and checking bags and boats for stowaway rats.
What the seabird survey found
The Isles of Scilly Wildlife Trust and the RSPB counted every breeding seabird across the islands in 2023. When they published the results in November 2023, they issued a call for action. Fewer than 7,000 breeding pairs remain, though Scilly still holds one of England's most important seabird colonies.
The headline findings were stark:
- Seabird numbers down nearly 20% since the previous survey in 2015
- Almost half the islands' seabirds lost over 30 years
- Common terns lost as a yearly breeding bird
- Kittiwakes likely to be the next to go
RecommendedSeasons & nightDark Skies on the Isles of Scilly: 9 Things to Do After Dark4 min read · Off-islandsRead the guide →Winners and losers
| Species | Change since 2015 |
|---|---|
| Lesser black backed gull | Down 58% |
| Herring gull (red listed) | Down 40% |
| Great black backed gull (amber listed) | Down 38% |
| Shag | Down by over a third |
| Common tern | No longer breeds every year |
| Manx shearwater | Doubled |
| Storm petrel | Significant increase |
The shag losses matter more than they might seem. Scilly has one of the largest shag colonies in the UK, so a drop of over a third here affects the whole country's population.
Why numbers are falling
The declines follow national trends and point to wider problems with the health of the ocean. The Wildlife Trust lists pollution, overfishing and damage to marine and coastal habitats as major threats. On land, rats eat seabird eggs and chicks. Bird flu was also confirmed on Scilly in August 2022.
The good news: removing rats works
Rats were removed from St Agnes and Gugh in 2013. Soon after, Manx shearwaters bred there for the first time in living memory, and storm petrels were confirmed breeding in 2015, according to the Wildlife Trust. By 2024 there were 154 shearwater pairs and 100 storm petrel pairs on the two islands.
Round Island, the second most important island for these species, was cleared of rats between January and April 2022. Today both species have more than 1,000 pairs each across Scilly. There is still a long way to go. In the 19th century, between 100,000 and 150,000 pairs of shearwaters may have nested here.
What happens next
Conservationists believe the shearwater decline can be fully reversed by removing rats from the remaining off islands, inhabited and uninhabited. The Wildlife Trust's Islands Officer is working with local people on Bryher, Tresco and St Martin's towards that goal. The proposals are still at the planning stage.
RecommendedBoats & waterIsles of Scilly Boats: Inter Island Times, Fares & Tips5 min read · From St Mary'sRead the guide →Removing rats is only half the job. The project's plans include keeping cleared islands rat free for 25 years. That means checking boats and freight, better waste management and new tools such as biosecurity dogs. Rat control on St Mary's would also be stepped up to protect the off islands.
How you can help
Small habits make a real difference on islands this size. The Wildlife Trust and the Seabird Recovery Project ask visitors to:
- Choose a WiSe accredited boat operator for wildlife trips
- Use binoculars and keep your distance from nesting birds
- Keep dogs on leads on beaches, where shorebirds may be nesting
- Take your plastic home to recycle
- Check bags, food and boats for stowaway rats, and report any you see
- Support the Isles of Scilly Wildlife Trust by donating, joining or adopting a species
Dog owners can find beach rules and seasonal restrictions in our dogs on Scilly guide.
Where to see seabirds on Scilly
Your seabird watching starts on the Scillonian, where you may spot gannets, guillemots, razorbills and even Manx shearwaters on the crossing. Once here, shags and gulls are easy to see from almost any shore. For puffins, you need to get out on the water during the breeding season.
Sea safaris, April to July
The best time for a seabird safari is April to July. Trips around Norrad Rocks, Annet, the Western Rocks and the Eastern Isles give you a chance of puffins, kittiwakes, fulmars and cormorants. From St Agnes, the Western Rocks wildlife safari runs on Wednesday afternoons in season.
RecommendedWildlifeScilly Birding: A Guide to Birdwatching on the Isles of Scilly12 min read · All islandsRead the story →Shearwaters at dusk and summer pelagics
Manx shearwaters gather in rafts on the sea in the evening before heading to their burrows after dark. Watching a gig race on a calm summer evening is a good way to see them. In July and August, offshore pelagic trips go in search of big shearwaters, skuas and storm petrels.
Scilly's seabirds have shown they can recover when given the chance. With careful visitors and a committed island community, the next survey could tell a happier story.
