Lundy seabird recovery: 25,000 Manx shearwaters after rat eradication

More than 25,000 Manx shearwaters now return to Lundy, up from about 600 in 2001. The change followed the removal of the island's rats, which had been eating the eggs and chicks of seabirds nesting in burrows.

After dark in spring and summer, the recovery can be heard. Manx shearwaters spend the day feeding at sea, then fly back low over the water and call to their mates from the slopes. The nests are hidden underground, so those night-time voices are often a better sign of the colony than anything visible from a cliff path.

Twenty-five years ago, far fewer calls came back. Lundy's national seabird census found only 7,351 birds in 2000, compared with around 80,000 in 1939. Puffins were close to disappearing from the island, and only 297 pairs of Manx shearwaters were recorded in 2001.

The recovery since then is unusually clear because the intervention was unusually specific. Conservationists identified rats as the main threat on land, removed them and then built a system to stop them returning.

Rats could reach nests hidden from almost everything else

Manx shearwaters make their nests at the end of burrows. The arrangement protects an egg or chick from weather and many larger predators, but it offers little defence against a rat moving underground.

Rats had reached Lundy on visiting ships and through shipwrecks. They fed on eggs and chicks before the young birds could leave the nest. Puffins, which also use burrows and crevices, faced the same pressure.

In 2002, the Royal Society for the Protection of Birds (RSPB), Natural England, the Landmark Trust and the National Trust began a joint eradication programme. Lundy was declared rat-free in 2006.

The declaration was not the end of the work. Boats still travel to the island, carrying people and supplies along the same route by which rats could return. Biosecurity checks, monitoring and a plan for responding to sightings became part of looking after the colony.

The shearwater population answered first

The latest public recovery summary records more than 25,000 Manx shearwaters on Lundy. The island now supports 95% of England's breeding population and has become one of the country's largest seabird colonies.

The scale of that increase is easier to grasp from the starting point. About 600 individual shearwaters were recorded in 2001. The current estimate is more than 40 times larger.

Puffins also rose from 13 birds in 2000 to a published count of 1,335, while European storm petrels began breeding on Lundy in 2014 and later exceeded 150 pairs. Across the island, the recovery summary puts the seabird population above 40,000, its highest level since the 1930s.

Those figures come from different kinds of count. Manx shearwaters are largely nocturnal on land and nest underground, while puffins and cliff-nesting birds can be counted from vantage points. Population estimates therefore depend on survey methods, breeding behaviour and the time of year, not a single headcount taken on one day.

This summer shows what rat removal cannot fix

Lundy Bird Observatory's July 2026 update found plenty of Manx shearwaters returning to the colony. Chicks were growing in productivity boxes, only one monitored bird had failed at the egg stage at that point, and roughly 500 birds had been handled during ringing evenings.

The puffin picture was more difficult. After severe winter storms around the Bay of Biscay and the coasts of Portugal and Spain, the observatory recorded a peak of just under 500 puffins this year, compared with about 1,350 in 2025. A survey at Jenny's Cove found roughly 330.

That fall does not undo the change since 13 puffins remained in 2000. It does show the boundary of the intervention. Removing rats made the breeding ground safer; it could not control winter storms, food availability, warming seas, pollution or the conditions birds encounter during migration.

Other species on Lundy are sending different signals this season. The observatory reported fewer occupied fulmar nests at Jenny's Cove, lower guillemot numbers and serious concern about lesser black-backed gull breeding success. Razorbills appeared to be having a stronger year. One island can hold a long-term recovery and a difficult breeding season at the same time.

An island can recover quickly when one pressure dominates

Islands give conservation teams a boundary that mainland projects rarely have. Once an invasive predator is removed, the sea limits the route back. That does not make eradication easy, but it makes the result more defensible if biosecurity holds.

The same principle has worked on other seabird islands because many species evolved to breed where mammalian predators were absent. When rats, mice, cats or other introduced animals arrive, birds that nest on the ground or underground can lose eggs and chicks at a rate the colony cannot absorb.

Lundy also shows why the years after eradication matter. The rat-free declaration came in 2006, but shearwaters, puffins and storm petrels needed repeated breeding seasons to turn safer nests into a larger population. Monitoring had to continue long enough to distinguish a durable change from one successful summer.

That long view separates Lundy from projects that can report activity but not yet an ecological result. England's Species Recovery Programme now funds work for 364 threatened species, while the UK seagrass restoration programme has planted millions of seeds. In both cases, survival and later population or habitat evidence still decide how much has been restored. On Lundy, two decades of counts now show the population response.

The next count will test the recovery again

Britain's wider seabird indicator remains weak. The official index was 37% lower in 2024 than at its 1986 starting point, with breeding failures, food shortages, disease, bycatch, pollution and climate pressures varying between species and places.

Lundy has not escaped that national picture. Its value is more concrete: one damaging pressure was removed from a breeding colony, the removal held, and tens of thousands more birds followed. The current puffin setback is a reason to keep counting, not to pretend the earlier recovery did not happen.

The island's night-time shearwater chorus now comes from a population that was close to being lost from Lundy. Keeping it depends on an unglamorous routine at the harbour, on boats and across the island: stop rats returning, watch the burrows and count what comes back.

Sources

• RSPB: Lundy's seabirds are on the up
• Landmark Trust: success for Lundy's seabirds
• Lundy Bird Observatory: 3 July 2026 summer seabird update
• GOV.UK: wild bird populations in the UK and England to 2024
• Feature image: puffins on Lundy by Lewis Clarke, Creative Commons Attribution-ShareAlike 2.0