Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Safeguarding Orkney's native wildlife from non-native invasive stoats.

Abstract

The Orkney Islands, off the north-east coast of Scotland, support highly significant cultural and natural heritage. The combined land area of the 70 islands is 990 km2 (380 sq mi), < 1% of the UK, but they host over 20% of the UK's breeding hen harriers (Circus cyaneus) (declining over much of its mainland range), 8% of breeding curlews (Numenius arquata) (one of only two UK populations not in decline) and an internationally important assemblage of breeding seabirds. The Orkney Islands are naturally free of mammalian predators, and all bird species, including raptors, are ground-nesting in the largely treeless landscape. Rats (Rattus spp.), hedgehogs (Erinaceus europaeus) and feral cats (Felis catus) are present across the archipelago. Stoats (Mustela erminea) are native to mainland UK but not Orkney, yet were detected on Orkney Mainland in 2010. Orkney Mainland has an area of 523 km2 (202 sq mi). Early attempts at removing them were not successful. By 2013 stoats were present across the Orkney Mainland and connected isles. In 2016, SNH and RSPB formed a partnership to eradicate stoats to protect the native wildlife and designated sites of the Orkney islands, and to secure the wider socio-economic and cultural benefits of thriving native wildlife. Difficulties faced in developing the project include predicting the effort required to remove stoats at a rate faster than they can reproduce, securing community support and access to private land and, in particular, funding large scale biodiversity restoration projects. A feasibility study determined that stoat eradication would be possible using DOC200 kill traps, and search dogs in later stages of the eradication. There are no legally available poisons that could be used on stoats in the UK. A Biosecurity Plan has been produced for the archipelago, with a current focus on preventing the spread of stoats to the un-invaded isles. The partnership is working to secure funds and community support for what will be the world's largest stoat eradication attempted to date. We present the findings of the feasibility study and our proposed methodology.