SNH: Stoats present real and long-term challenge on Orkney

The unwelcome predator has been introduced over the past five years. There is some evidence its presence could lead to significant dips in populations of Orkney voles and hen harriers.

There is also concern that stoat numbers, if unchecked, could affect the wildlife tourism industry by depriving it of species of interest for visitors to watch.

For instance the value to Scotland’s economy of nature based tourism is £1.4 billion a year and 39,000 jobs (full-time equivalent) are reliant on Scotland’s nature-based tourism. Figures for Orkney from 2011 show sustainable tourism ‘gross value added’ £14.2 million.

Stoats, the report states, are likely to be present in sufficient numbers to cause a population dip in the numbers of Orkney voles.

There are 380 ‘reliable’ sightings of stoats since 2010, with detections going up since initial records in that year.

The new report involves wildlife management experts at the University of Aberdeen. They have advised on the impact the stoats could have on the ecology of the Orkney islands and provide advice on potential solutions.

And the stoats could also have a negative impact on already scarce populations of hen harriers and short eared owls by depriving them of prey.

The report concludes that management of the stoats is required to reduce or remove the population. To meet this challenge SNH has established a technical advisory group made up of experienced staff from SNH; renowned academics and representatives of partners like RSPB with the aim of bringing a management project forward, securing funding, and establishing a plan of action.

SNH believes this must be delivered with the support of the community and land management sectors, and is keen to work with them and welcome their interest as the project is developed.

Graham Neville of SNH said: “Orkney is fortunate to have such a diverse and high quality landscape and natural heritage - rich in bird life from Arctic tern, with one of the longest of all migratory passages, to short eared owl and red throated diver.

“Arable land complements cliff colonies and the seas around Orkney are teeming with life and marine plants.

“That makes it plain we have a duty to conserve its nature. And the report tells us it is highly likely that invasive non-native stoats will change the ecology of Orkney. That will have a heavy impact on its place as a home for birds of prey and other species.

“This is a significant issue with implications for the affected species of Orkney – but no one should be in any doubt it will be difficult to remove stoats and it will take major funding to achieve removal.

“Our maps of stoat records are a conservative estimate of the distribution of stoats on Orkney and we estimate that in reality the majority of mainland and connected islands will be occupied by stoats now, or in the very near future.”

The commissioned report ‘stoats on the Orkney Islands – assessing the risks to native species’ dealt with all scenarios on the likely impact of the stoat introduction.

The Stoat Technical Advisory Group first met on 26 May and has advised on the immediate next steps that SNH and partners must now carry out to establish what should be done about the stoat problem.

Stoats are, like most predators, opportunistic, and take rabbits, rodents, game birds, waders, chicks and eggs. And they have been shown to predate hen harrier chicks.

They are established on Shetland but at moderate to low numbers and with no major impact on local species. This is thought to be due to the lack of equivalent species to the Orkney vole.