Orkney vole  (Microtus arvalis orcadensis)

Not legally protected in the UK. No conservation designations (4). The common vole, Microtus arvalis, is listed as Least Concern on the IUCN Red List (1).

The Orkney vole is an endemic subspecies of the common vole (Microtus arvalis), which is found only in the Orkney Islands, Scotland. It is larger than the common vole, and is similar in appearance to the field vole (Microtus agrestris), but has shorter paler fur (2). Like all voles it has a stocky body with a blunt, rounded snout.

Found on the islands of Rousay, Mainland, Sanday, Westray and South Ronaldsay in the Orkney Islands, Scotland. The subspecies was introduced to the islands 5,000 years ago, possibly on the boats of Neolithic settlers (3).

Inhabits old peat cuttings, grassy areas, drainage ditches, road verges and other linear habitats (3).

The Orkney vole is active during the day and night, but it tends to be more active during the day (3), and usually returns to its burrow to rest every 3 hours (2). These voles feed mainly on leaves, stems and roots of grasses and other plants, and seem to preferentially feed on plants with high nitrogen content (3).

The breeding season occurs between March and November, and successive litters consisting of between 1 and 6 young are produced each month. The young voles breed in the year after their birth, and typically die before the end of that year (3). Main predators are domestic cats and various birds of prey; in fact, Orkney voles represent a very important component of the diet of the Orkney Islands' birds of prey (2).

At present the population of this subspecies is very fragmented, in small patches of natural or semi-natural habitats. Linear habitats such as fence lines and road verges act as corridors, linking fragmented patches of habitat together and allowing voles to pass between sites (3). As this subspecies is so reliant on these linear habitats, their removal or alteration could therefore impact hugely upon Orkney vole populations (3).

There is currently no conservation action targeted at this species. It is not protected by law (3).

For more on this species see:

• People’s Trust for Endangered Species - Orkney voles:
  http://ptes.org/index.php?page=160