This begins in March and may carry on through the summer into early winter, depending on the weather. A nest is made of woven grass stems and this is usually below ground in a burrow, or it may be at the base of sedges on marshy ground. After a gestation period (time between mating and birth) of 20 - 22 days, the female gives birth to up to eight young, usually five. The babies are blind and naked at birth and weigh only 5 grams. During its first week of life a baby vole puts on 1 gramme in weight per day. At five days old, they have grown their furry coats and their eyes are open three days later.
At fourteen days, the young are weaned and are about half the normal adult size. Young voles are a very dark brown with an almost black tail and are sometimes found away from water in damp woodland and grassy areas.
Females usually have three or four litters in a year and sometimes the young of the first litter may produce litters of two young by the end of the summer.Read More: Water Voles and Humans