Baby Bank voles are born in nests made of grass, moss and feathers. The nests are built above ground, usually in trees. When the babies are born they have no fur and are blind. They live on their mothers milk for the first few weeks of their life. A mother Bank vole has an average of six babies at a time, and can have five litters in a season. A baby Bank vole born in spring will be old enough to breed by the time fall comes. A Bank vole lives for an average of 18 to 20 months.