A New Era for Orkney’s Wildlife
The efforts to eliminate invasive stoats from Orkney have led to a remarkable resurgence in the islands’ native wildlife, particularly the Orkney vole and some of Britain’s rarest birds of prey. This success story highlights the positive impact of targeted conservation initiatives on fragile ecosystems.
Record Vole Activity
A recent report has shown that vole activity in spring 2025 reached its highest level since 2019, when a major project to protect Orkney’s wildlife from non-native predators was initiated. The findings indicate that the vole population is thriving, which is a crucial factor for the survival of several bird species that rely on them as a primary food source.
This recovery is not only significant for the voles but also for the rare hen harriers, which have seen an increase in breeding attempts. The 2025 season marked their most successful year since the project began, demonstrating the direct link between vole numbers and the health of these birds of prey.
In addition to hen harriers, the breeding numbers of short-eared owls have also increased compared to six years ago. Conservationists are celebrating these results, stating that the eradication of stoats is already transforming the ecosystem on the islands.
The Threat of Stoats
Stoats, originally native to mainland Britain, were first observed on Orkney in 2010. Their presence posed a serious threat to the indigenous Orkney vole, a species found nowhere else on Earth. Experts warned that without intervention, stoats could devastate local wildlife populations.
One particularly concerning discovery was that stoats have been found to store up to 100 Orkney voles in their food stores, highlighting the severity of the threat they pose.
Since 2019, over 8,500 stoats have been removed using humane traps, making it the largest eradication of the species on an inhabited landscape anywhere in the world. The monitoring report revealed that vole activity hit record highs in 2025, with signs of voles found in a third of the 1,082 small survey squares searched across 22 sites in Mainland, Orkney, and the linked South Isles.
Autumn activity levels were also high, indicating a strong recovery of the vole population.
Benefits for Birds of Prey
Hen harriers, one of the UK’s most threatened birds of prey, have also benefited from the decline in stoat numbers. In 2025, volunteers from the Orkney Raptor Group recorded breeding at 74 sites on islands where stoats live, marking the birds’ best year since 2012. Despite challenges such as relentless wet weather during a critical stage, nearly 60 chicks are believed to have successfully fledged from monitored nests, contributing significantly to the UK’s total population of around 650 breeding pairs.
Short-eared owls, though more difficult to monitor, were confirmed at 55 sites on islands with stoats during the breeding season. Definite breeding was recorded at 16 locations, with nests found at an additional six. Experts note that the figures show a steady rise in short-eared owl breeding sites since the stoat removal programme began in 2019.
Both hen harriers and short-eared owls rely heavily on Orkney voles to feed themselves and their young, with strong vole numbers directly linked to breeding success within these species.
Ongoing Conservation Efforts
The stoat eradication effort is being led by the Orkney Native Wildlife Project, a partnership between RSPB Scotland, NatureScot, and Orkney Islands Council. The project also aims to protect other vulnerable species such as curlews, a ground-nesting bird with a nationally significant population on the islands.
The initiative uses specially trained detection dogs to track stoats, alongside strict biosecurity measures to prevent the predators from spreading to stoat-free islands.
Matt Marsh, monitoring officer for the project, said: “It’s fantastic to see the continued positive impact that removing stoats from Orkney is having on our native wildlife. Hen harriers are one of the most fascinating species we monitor, as well as being one of the rarest birds of prey in the UK, so it’s excellent to see that their numbers are increasing.”
He added: “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.”
Anne McCall, director of RSPB Scotland, said: “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. There are many factors that influence survival. However, to give species like the Orkney vole their best chance, removing invasive non-native species like stoats from islands is essential.”
Success Beyond Orkney
This is the latest success for island invasive species eradication projects around the UK, following the recent announcement that feral ferrets were successfully removed from Rathlin Island off the Northern Irish coast. This effort has helped protect thousands of breeding seabirds and other rare birds.
