Voles

There are about 50 species of voles. Most voles are included in the genus Microtus. The meadow vole (M. pennsylvanicus) is the most common and widespread species of vole in North America, occurring through most of Canada south of the high arctic tundra, and in most of the northern United States. The meadow vole is a familiar species of fields, wet meadows, and disturbed forests. Because of its wide distribution and periodic irruptions of abundance, the meadow vole is both ecologically important as a component of ecological food webs, and economically important as an occasional pest.

The tundra vole (Microtus oeconomus) is another widespread species, occurring in arctic tundra and open boreal forests of Alaska, Yukon, and Eurasia. The woodland vole (M. pinetorum) is widespread in forests of southeastern North America. The montane vole (M. montanus) occurs in alpine grasslands and tundras of the mountains of the western United States. The prairie vole (M. ochrogaster) occurs in the grasslands of the interior of the continent, while the rock vole (M. chrotorrhinus) occurs in boulder slopes and other rocky places in northeastern North America. The chestnut-cheeked vole (M. xanthognathus) occurs in local populations in the boreal forest of northwestern North America. The long-tailed vole (M. longicaudus), singing vole (M. miurus), Townsend's vole (M. townsendii), Richardson's vole (M. richardsoni), and California vole (M. californicus) are all species of coniferous forests of western North America.

The heather vole (Phenacomys intermedius) occurs widely in boreal and northern temperate forests of Canada and the northwestern United States. This species is very similar in appearance to the meadow vole, and was overlooked as a distinct species by most field biologists until the 1950s, when reliable, diagnostic characters were discovered (these involve the shape of the cheek teeth).

The northern red-backed vole (Clethrionomys rutilus) occurs in tundra and open boreal forests of northwestern Canada and Alaska, and also in Siberia and eastern Scandinavia. There is also a disjunct population in coniferous rain-forests of Oregon and Washington. Gapper's red-backed vole (C. gapperi) occurs more widely throughout temperate North America, reaching as far south as the mountains of Arizona.

The sagebrush vole (Lagurus curtatus) occurs in high altitude sagebrush steppes and semi-deserts of southwestern North America. Richardson's water vole (Arvicola richarsoni) is a species of alpine meadows and streams of the Rocky Mountains.