Orkney Stoat Eradication Project Delivers Major Boost to Native Wildlife
A comprehensive new report has highlighted the remarkable success of the Orkney stoat eradication initiative, revealing a significant resurgence in native vole populations and a positive impact on some of the UK's rarest birds of prey. The findings underscore the critical importance of targeted conservation efforts in protecting vulnerable ecosystems from invasive threats.
Record Vole Activity Signals Ecological Recovery
Monitoring data from spring 2025 shows that Orkney vole activity has reached its highest level since the project began in 2019. Surveyors recorded signs of voles, such as droppings and grass clippings, in 358 out of 1,082 small squares across 22 sites on Mainland Orkney and the interconnected South Isles. This represents a third of the surveyed areas, indicating a robust recovery for a species found nowhere else on Earth. Autumn activity levels were also notably high, suggesting sustained population growth.
Matt Marsh, monitoring officer for the Orkney Native Wildlife Project, expressed enthusiasm, stating, "Orkney voles are found nowhere else in the world and are the species that is probably most threatened by the arrival of stoats, so to see historically high rates of vole activity is very encouraging." The voles serve as a crucial food source for predatory birds, making their recovery a linchpin for broader ecological health.
Hen Harriers and Short-Eared Owls Thrive Post-Eradication
The removal of invasive stoats has directly benefited rare bird species that depend on voles for sustenance. In 2025, volunteers from the Orkney Raptor Study Group documented hen harriers breeding in 74 locations on islands affected by stoats, marking the best year for this endangered bird of prey since 2012. Despite challenging wet weather that led to chick mortality, nearly 60 chicks successfully fledged from monitored nests, contributing to the UK's overall hen harrier population of around 650 pairs.
Similarly, short-eared owls showed promising signs, with confirmed presence at 55 sites during the breeding season. Definite breeding occurred at 16 locations, with nests found at an additional six sites. The conservation team noted a continued increase in breeding sites for these owls since the stoat removal efforts commenced in 2019. Both species rely heavily on Orkney voles to feed themselves and their offspring, linking their breeding success directly to vole abundance.
Large-Scale Eradication Efforts and Future Goals
Since 2019, over 8,500 stoats have been humanely removed using lethal traps in what is described as the largest stoat eradication on an inhabited landscape globally. The Orkney Native Wildlife Project, a partnership between RSPB Scotland, NatureScot, and Orkney Islands Council, aims to protect not only voles and raptors but also other species like curlews, which have a nationally significant population in Orkney. The project employs detection dogs and biosecurity measures to prevent stoats from colonizing stoat-free islands.
Anne McCall, director of RSPB Scotland, emphasized the project's broader implications, saying, "The Orkney Native Wildlife Project is showing that we can halt and reverse species declines if we take action to address the threats wildlife is facing. Invasive non-native predators are a significant threat to much of the iconic wildlife found on Scotland's islands." She added that removing such species is essential for giving native wildlife like the Orkney vole their best chance at survival.
Context and Conservation Success Stories
This achievement follows other successful invasive species eradication projects in the UK, such as the removal of feral ferrets from Rathlin Island off the Northern Irish coast, which protected thousands of breeding seabirds and rare birds. Stoats, native to mainland Britain but not to Orkney, were first detected on the islands in 2010 and posed a severe risk to local wildlife, with individual stoat food stores containing up to 100 Orkney voles discovered. Without intervention, conservationists warned that stoats could devastate these unique populations.
The report's findings highlight the effectiveness of coordinated conservation strategies in restoring ecological balance. As efforts continue, the project serves as a model for invasive species management worldwide, demonstrating that proactive measures can lead to tangible recoveries in biodiversity and support for endangered species.
