The Bank Vole-Clethrionomys glareolus

The bank vole is a small, chubby mammal that inhabits hedgerows, woodland and scrub. Although rarely seen this is probably one of the most common mammals in these habitats. They also live in grassland and sub urban gardens, although in these localities the field vole and the wood mouse, respectively, are likely to be commoner.

The main reason they are not often encountered is that they tend to stay well hidden, and studies have shown that in the summer months they become increasingly more nocturnal in their activities.  they go about their business under cover for they are prime targets for birds of prey , foxes and other carnivorous mammals.

hedgerows and woodland that have bramble thickets in their proximity, will almost certainly play host to several bank voles. In a patch of bramble their could be up to half a dozen bank voles living there. 

Description of the Bank vole.

Photograph courtesy of Evan James {hymo}, creative commons attribution


Courtesy of Nordeich CC BY-SA 3.0 License.Rötelmaus.jpg

As previously mentioned bank voles stay with thick cover where possible, thus when they are observed, it is usually in the form of a brown blur darting back into cover. It is about the size of a mouse but it has a more bulkier appearance.The head and body length is about 9cm the tail a further 3-4 cm. Their ears are rounded and barely project above the fur. The adult weighs around 20-25 gm. Fully grown males are approximately 20% longer than the females.

Bank voles have a more chestnut coloured fur above, which readily distinguishes them from the greyish brown colouring of the field vole. The belly is creamy coloured or greyish in some individuals. The tail is less than half the length of its body, it is black above and white below.

The blunt chubby face { another characteristic of voles} is another distinguishing feature from the sharper features of the mouse, has long whiskers. Living as they do in shallow burrow systems these whiskers help them to find their way around.

The short legs are almost hidden by the fur. Although these legs are small they are also strong which make them excellent climbers. the eyes are dark and small. 

Life style of the bank vole

bank voles dig shallow burrow systems, this may be excavated in loose soil or leaf litter. they will also take advantage of ready made tunnels such as mole runs or the natural runways among tree roots. Unlike the mainly nocturnal wood mouse , bank voles are active by day and by night although the main periods of activity seems to around dawn and at dusk.

The diet of this industrious mammal  is very varied and their survival is very much enhanced by this fact. Almost anything they happen upon can be made into a meal. They eat moss, lichen, new roots, flower and leaf buds, bark of young trees especially the bark of saplings, worms , insects or even dead leaves.

The gnawing of bark that is more prevalent in the winter months may cause considerable damage in young plantations. Thus, they are much disliked by Foresters, because of this fact and also because the bank vole eats seeds,flower and leaf buds, which hinders regeneration. They also like to feed on hazel nuts which they open in a specific way. They gnaw a hole , usually in the side, which is neat, has a sharp edge and evident teeth marks, which differentiate them from the larger more ragged hole created by the wood mouse. 

Whether it is green hazel nuts of autumn or the young flower buds of spring they are food to the bank vole.

Breeding and young.

The breeding season usually commences in March or April { Although less frequently they will breed in winter if conditions are favourable}.

The nest of the bank vole is constructed out of leaves and chewed grass usually within a chamber of a shallow burrow. The females are pregnant for around 21 days normally, although they can give birth at 17 days if conditions are favourable. Between 4 and 5 litters are produced  with 3-5 young making up the each litter. The females are very protective of their young. If any young strays away from the nest she will go and locate them and carry them back. the babies weigh about 2gm at birth and are blind, naked and helpless. they are suckled by their mother for about three weeks

Studies have revealed that the young are capable of producing high pitched squeaks. They are to high for humans to hear but they can be heard by the mother from some distance. the young are capable of breeding themselves at the age of 4-5 weeks.

These young voles are almost ready to leave the nest and will be capable of breeding very soon

Photograph courtesy of plant surfer Creative Commons Attribution



Conservation issues..

Until the late 1950s bank voles did not occur in Ireland, but, following introductions {probably accidental from ships} they have begun to spread from the south west. Ireland is rich in bank vole habitat and these fecund little mammals will continue to thrive and spread in distribution terms.

There are no current conservation issues in the UK for the bank vole. 

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