It’s Invasive Species Week: 12–18 May 2025

Rathlin Island, off the northern coastline of Northern Ireland, is well-known for its seabirds, and has the largest population of breeding Guillemots in the whole of the UK. However, these seabirds are threatened by two invasive non-native species: Ferrets and Brown Rats, who have few native predators and eat the eggs and chicks of Puffins, Guillemots and other seabirds. 

In 2021, a multi-partner and funder project was launched to restore the island. The team set ferret traps every 250 metres across the island. There hasn’t been a single verified sighting of a Ferret since October  2024, and we are hoping to be Ferret-free later this year. The focus is now on eradicating all the rats from the island, to ensure that seabird chicks can thrive. For more details on LIFE Raft, see here.

The Orkney Islands are home to many vital UK species, including the Orkney Vole which is only found in Orkney, and nowhere else. But in 2010, Orkney’s wonderful wildlife was threatened when Stoats were reported for the first time. Stoats are native to mainland Britain and a valuable part of our wildlife – but they don’t naturally occur in Orkney, where sensitive species cannot cope with this new predator. 

In 2019, RSPB Scotland joined forces with a team of partners and formed the Orkney Native Wildlife Project, with the aim to eradicate Stoats from the island. They use detection dogs (called Spud, Scout, Thorn, Red, Skye, Bodie, Fizz, Pongo and Charlie) who work closely with their handlers to sniff out where the Stoats are. The project is still ongoing, but signs indicate that there has been a 200% increase in the numbers of the Orkney Vole. Find out the details here.  

The Biosecurity for LIFE project was a partnership project between the RSPB, the National Trust and the National Trust for Scotland, and ran from 2018 to 2023.  

Working with a range of different stakeholders, the project aimed to safeguard seabird islands against the threat of invasive non-native mammals such as rats, mice, Mink and feral cats, under the heading of ‘Save Our Seabirds’. It focused on 42 Special Protection Areas (SPA) - some of the most important seabird islands in the country. These areas include Skokholm and Skomer in Wales, the Isles of Scilly in England, St Kilda in Scotland, and Copeland Island in Northern Ireland. Officers created ‘biosecurity plans’ with each SPA’s owners, managers and communities, giving detailed advice on the likely ways invasive predators might reach each island, and how to prevent this happening, and a response procedure should one reach the island. 

The result is that island owners, managers and communities on 95% of the 42 SPA islands are now fully equipped to manage non-native invasive species effectively. Read more about the project here. 

This project looks at the biosecurity measures at the borders of five Caribbean UK Overseas Territories, including the Turks and Caicos Islands, Montserrat, Cayman Islands, British Virgin Islands and Anguilla. The islands of the Caribbean have many unique plant and animal species, but these are under threat from invasive non-native species such as rats, feral cats, mongoose and Green Iguanas. 

The project seeks to prevent new invasive non-native species from entering these countries and putting rapid response procedures in place. By focusing on borders, the aim is to prevent the introduction of new or existing non-native invasive species into these areas, as a preventative measure. The project also builds capacity of local teams, so they are equipped to deal with any incursions.  

The Sister Islands Rock Iguana lives on the Cayman Islands of Cayman Brac and Little Cayman, and nowhere else in the world. It was once abundant on both islands, but it has suffered severe population declines in recent years. Camera trap footage has shown clear evidence that the hatchlings and juveniles are affected by predation from feral cats. 

The Department for the Environment, the National Trust for the Cayman Islands and the RSPB joined forces in 2021 (with funding from Darwin Plus) to control the feral cat populations and promote responsible pet ownership. 

Since feral cat control began in 2022, the population of Sister Islands Rock Iguanas has increased from a low of around 1,000 individuals in 2022, to around 3,500 in 2025. This is even higher than the highest population estimate in 2014, when the first survey was undertaken. 

In addition, the Little Cayman community have worked together to achieve 100% cat registrations on the islands, ensuring all pet cats are microchipped, vaccinated and spayed/neutered, to avoid them bolstering the island’s population of feral cats. 

The mountain tops of the island of St Helena, in the South Atlantic Ocean, are home to fragments of the UK’s last natural cloud forest, containing approximately 250 species that exist nowhere else on earth, and are perfectly adapted to the cloud forest habitat. The cloud forest is also vital for capturing water from the mist, which contributes to around 60% of the island’s fresh water. 

However, invasive plant species are a constant threat: they outcompete endemic plants, which causes degradation and fragmentation of the habitat. The St Helena Cloud Forest Project, where the RSPB is an international partner, works to remove invasive plant species from key areas, restore areas of the cloud forest, connected fragmented sections, and create new areas of habitat. Thank you to the Foreign Commonwealth and Development Office for funding this project.

Anguilla has a range of habitats, from coastal forests, scrubland, mangroves and coral reefs to globally important salt ponds that are vital for wading birds. Globally-important seabird populations also breed on its offshore cays. However, Anguilla’s rich biodiversity is under threat from invasive non-native species. 

Here, in a project funded by Darwin Plus and led by Re:Wild and the Anguilla National Trust, local teams are using AI to help identify invasive species, using technology originally developed for monitoring tigers and rhinos. The software is trained with photos and 3D models of the target species, so it can now identify a range of invasive species, including mice, rats, cats and goats, even if the animal if partly hidden. It will soon be deployed in restored species-rich areas in the Anguilla mainland and offshore islands, and the cameras will instantly send images of any target species directly to conservation managers’ smartphones. This enables a rapid response, which will enhance biosecurity efforts in the area.  

This is a major step forward in invasive species monitoring, so we can expect similar projects to take place on other Caribbean islands, and other islands, worldwide. 

Above image: The camera trap detects species in the area and can alert conservationists of any that are invasive.