ABSTRACT
There are four species of red-backed voles in the genus Clethrionomys. Clethrionomys glareolus, the bank vole, has an extensive geographic distribution, being found in most of Europe, the British Isles, and Scandinavia and extending to Asia Minor and western Siberia. C. rutilus and C. rufocanus also occur in the Old World. Two species of Clethrionomys occur in North America, C. gapped and the more northern representative, C. rutilus. Bank voles are active throughout the year and usually breed from March through September. Winter breeding is the exception rather than the rule. The species of Clethrionomys display multiannual cycles of abundance, as do other microtines.
