St Agnes from Gugh with the Western rocks in the background. Photo: Jaclyn Pearson.

The Isles of Scilly, 26 miles of the tip of Cornwall have five inhabited islands (St. Mary’s, St Agnes and Gugh, St. Martins, Tresco and Bryher) with a population of 2,000 mainly living on St. Mary’s. Scilly is home to 13 breeding species of seabirds including puffins.

Over 65% of the land across Scilly is managed by the Isles of Scilly Wildlife Trust and a partnership of organisations, including the RSPB deliver actions to protect seabirds on both the inhabited islands and the 140 uninhabited islands. This included the ‘Isles of Scilly Seabird Recovery Project’ removing the rats from St Agnes and Gugh in 2013.

Manxie chick

Jaclyn with the first Manx shearwater chick seen in living memory (2013) due to removal of the rats on St Agnes. Photo: Nick Tomalin.

By removing rats from St Agnes and Gugh, the nearby uninhabited Western rocks (which are the most important seabird breeding islands) are protected from any rats which could have potentially swam the 1km swimming distance. On the other side of St Agnes and Gugh, a deep 2k water channel separates St Agnes from any incursion of rats swimming back from St Mary’s. If (or when) rats return to St Agnes, it will likely be from boats.


St Agnes as seen from Western Rocks island of Annet, a short swimming distance for rats. Photo: Ed Marshall.

The archipelago has a rich maritime history of ship wrecks, it is likely that rats swam ashore to St Agnes and Gugh in the 1700’s. The uninhabited islands which have never had rats remain strongholds for seabirds and the action now is to do the same for St Agnes and Gugh, to remain rodent free through biosecurity.

The residents of St Agnes and Gugh do something very special - not only do all the residents remain vigilant for rodent sign, ensure high risk freight items are checked and ask visitors to assist - a group of 25 volunteers carry out biosecurity monitoring checks monthly.

Known as the ‘Seabird Heritage Volunteers’ they maintain biosecurity stations around the island which contain wax blocks flavoured with chocolate or peanut butter (flavours favoured by rodents). If a rat does return, they will seek out food and gnaw marks left in the wax will be detected by the volunteers.

D7AB7A83 7430 4165 99A6 2F0BD1965F30 1 105 c

Seabird Heritage Volunteer Coordinators, John and Trish Peacock with a wax block, biosecurity sticker and volunteer hats. Photo: Jaclyn Pearson

This community knows all too well what the impacts of rats are to an island. Not only predating the seabirds, but rats impact their businesses and day to day lives as farmers, fisherman and tourist accommodation providers. When asked about their momentum to continue to carry out monthly biosecurity checks, they explained that prevention is better than cure. The seabirds are thriving, and they don’t have to worry about rats gnawing through goods, vegetables, lobster pots or being inside buildings. They like it rat-free and will work hard to keep it that way into the future.

CF376EB9 CC6D 4FAB 8F2E 409C1FFE90D3 1 105 c

Lesser white-toothed shrew teeth marks on chocolate wax – not a rat! Photo: Jaclyn Pearson

Jaclyn recently carried out an audit of the biosecurity stations and the incursion shed as part of in her Biosecurity Officer role and was thrilled to see the care and motivation this community continue to have.

She is keen that the Volunteer Coordinators share their experiences with other inhabited islands. The legacy of protecting seabirds through biosecurity can be done, giving a great sense of great achievement.

50523E29 44D3 4E12 96D7 0C0735D35075 1 105 c

Jaclyn thanks the residents of Gugh for their ongoing biosecurity. Photo: Jaclyn Pearson

Find out more about the Isles of Seabird Recovery Project at



July 2021

A long day trip to the Flannan Isles

In this blog our Biosecurity Officer Sarah recounts a long and tiring day to the Flannan Isles to set up rodent surveillance and count the seabirds.

July 2021

Sula Sgeir - 19/06/2021

In the last blog we followed Tom on his journey to North Rona. Here we pick up the story aboard Enchanted Isle heading west towards Sula Sgeir.

April 2020

Skokholm, Skomer and Middleholm

Together these islands are estimated to hold a remarkable 67% of the world population of breeding Manx shearwater. These birds are diurnal but will only come ashore or go out to sea under the cover of darkness and nest underground so you’re unlikely to see them when you visit the islands unless you stay overnight. You will see that the ground is covered in burrows and is therefore extremely fragile so take care to stay on the paths when you visit. Skokholm is also home to the fourth largest storm petrel colony in the UK, holding 8% of the UK breeding population. These birds’ nest in crevices in stone walls or quarries and are also nocturnal when on land to avoid predation. The islands most famous resident however is the puffin, these birds nest underground but come out in the day so you are likely to see rather a lot of them if you visit between April and July. All these ground-nesting species are particularly susceptible to invasive non-native mammalian predators, they would not survive if rats, mink or stoats arrived on the islands.

Illustration of birds

Contact Us

If you’d like more information or would like to report a sighting of an invasive predator please contact us using the form below: