Water vole

This large rat-sized vole lives along a range of watercourses. The signs of vole activity include holes of around 50mm diameter connected with worn runs through waterside vegetation and characteristic prominent toilet sites, with greenish rice shaped dung. Approach the water’s edge slowly and quietly and listen for the sound of vegetation being gnawed. Water voles will dive under the water with a loud plop, if disturbed.  They do not have webbed feet and swim under water with some difficulty. They appear more buoyant in the water than a brown rat and have a short furred tail.

Water voles are present in their territories throughout the year, but spend more time underground during the winter, feeding on roots and tubers. They are more visible in the summer and autumn as there are a greater number of dispersing juveniles and adults are highly territorial.
Found from lowland rivers and ditches to narrow mountain burns of the Highlands, this animal is highly adaptable to a range of wetland habitats. They inhabit the water ditches of Edinburgh Airport and can be found in water channels of 30cm width on the top of the Cairngorms plateau.  The lowland animals tend to be brown in colour, while the mountain and upland animals are more often very dark brown or black.
This species is under severe threat from predation by the introduced, non-native American mink. Their numbers have been severely reduced in accessible areas to leave a total population of less than 10% of its original size.

Orkney vole

Microtus arvalis orcadensis

A vole has small ears, a tail shorter than its body length and a rounded head. An Orkney vole is twice the size of the field vole, which is found across the rest