Bank voles are active during both the day and night, although they become increasingly nocturnal during the summer (4). They do not hibernate in winter, but are active throughout the year (4). They have a broad diet, which is mainly herbivorous, including fruit, soft seeds, leaves, fungi, roots, grass, buds and moss. They may also occasionally take invertebrate food such as snails, worms and insects (4), and the odd bird egg may be eaten (2). Breeding typically takes place between April and October, but when conditions are suitable, births may occur throughout the year (4). Ovulation by the female is stimulated by the presence of a male, possibly via certain scents that males produce (5). Gestation takes around 21 days, but may be a short as 17 days in this species if conditions are optimal (5). Between 4 and 5 litters are produced in a year, each one consisting of 3-5 young (4). Females are able to conceive again whilst still suckling the previous litter; under these circumstances the gestation period will be longer, up to 24 days (5). The young voles are born in a nest, which is usually located underground (5). Males do not assist with rearing the offspring. Females are very protective of the litter; if any young leave the nest the female locates them and carries them back to the nest (5). The young become sexually mature at around 4.5 weeks of age, however those born later in the year will not start to breed until the next spring (4). Predators such as owls, kestrels, foxes and weasels take their toll on vole populations; the maximum life span for this species is 18 months. The numbers of bank voles varies greatly throughout the year, being high towards the end of summer and plummeting through the winter to a low in April (4).

The bank vole has a small, stocky body and a blunt, rounded muzzle (2). The upperparts may be yellowish, reddish or brown in colour, the flanks are greyish and the rump is whitish-grey (2). The short tail is usually slightly bushy at the tip (2).

The bank vole, Myodes glareolus has a wide range in the Palaearctic which stretches from the British Isles through continental Europe and Russia to Lake Baikal. In the north, its range extends beyond the Arctic circle, and in the south it reaches northern Turkey and northern Kazakhstan (Shenbrot and Krasnov 2005). It is widespread in Europe, although it is absent from southern Iberia and the Mediterranean islands. It is found from sea level to 2,400 m (Spitzenberger 1999).

Palearctic: Myodes glareolus is found from Europe through Central Asia (Macdonald 2001; Jonsson et al. 2000). Populations have frequently been recorded in Finland (Oksanen et al. 2001; Yoccoz et al. 2001; Oksanen et al. 1999; Prevot-Julliard et al. 1999; Horne and Ylonen 1996, 1998; Koskela et al. 1998; Koskela et al. 1997) and the United Kingdom (Bellamy et al. 2000; Flowerdew and Gardner 1978).

Biogeographic Regions: palearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Exotic

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Europe, parts of Asia Minor, and central Asia (Nowak 1991). Introduced and established in Ireland (Nowak 1991) and Newfoundland (Joe Brazil, pers. comm., 2000). Brazil last checked the population on Yellow Fox Island, Notre Dame Bay, Newfoundland, in 1986. Specimens from that survey are in the National Museum in Ottawa, the Newfoundland Museum in St. John's, and in Brazil's possession. This vole was introduced to this small island in the mid- to late 1960s by Dr. Bill Pruitt and/or one of his students. The island is not large, less than a square kilometer. Brazil stated he had no reason to believe that the voles are not still thiving on the island. They have no competitors and few if any predators.

Common in Britain, including a number of the islands. On Skomer Island off the Pembrokeshire coast of Wales, there is a subspecies known as the Skomer vole (Clethrionomys glareolus skomerensis). The bank vole is also common throughout much of western and central Europe (4).

Adult bank voles reach a head-body length of 10-11cm and a weight of 17-20g, with males and females being approximately the same size. The tail is less than body length and reaches a length of 3-4cm. Bank voles are small with small eyes and ears. Their body is covered by thick fur in shades of brown or gray. Their muzzle is blunt and rounded. Relative to body size, M. glareolus has a small brain. Teeth are prismatic and are characterized by flat crowns, which are adapted for their herbivorous diet (Macdonald 2001).

Range mass: 17 to 20 g.

Range length: 10 to 11 cm.

Type for Myodes glareolus
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Mammals
Sex/Stage: Female;
Preparation: Skin; Skull
Collector(s): T. Stejneger
Year Collected: 1898
Locality: Bergen, Bergen Municipality, Hordaland, Norway, Europe

Type for Myodes glareolus
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Mammals
Sex/Stage: Male;
Preparation: Skin; Skull
Collector(s): R. Young
Year Collected: 1899
Locality: Montrejeau, Haute-Garonne Department, Midi-Pyrenees, France, Europe

Type for Myodes glareolus
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Mammals
Sex/Stage: Female;
Preparation: Skin; Skull
Collector(s): J. Loring
Year Collected: 1898
Locality: Uppsala, Uppsala Municipality, Sweden, Europe

Habitat and Ecology

Systems

• Terrestrial

Bank voles are found in a wide variety of habitats, including forests, scrub forests, hedges, banks, and swamps (Macdonald 2001; Bellamy et al. 2000). They appear to prefer deciduous, coniferous, and taiga forests (Yoccoz et al. 2001; Prevot-Julliard et al. 1999; Koskela et al. 1998; Koskela et al. 1997; Ostfeld 1985).

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: taiga ; forest

Wetlands: swamp

Other Habitat Features: agricultural ; riparian

This adaptable species (2) inhabits broadleaved woodlands, scrub, parks, hedgerows and banks where there is plenty of herbaceous cover (4).

Myodes glareolus have been characterized as omnivorous (Ostfeld 1985) and herbivorous (Macdonald 2001). When eating grass, M. glareolus clip the stalks and lays the clippings in piles. Food is obtained in the winter by burrowing underground. In the summer and fall food is cached. Diet changes with season and location but includes green parts of plants (Macdonald 2001), fruits and seeds from available trees, such as the European ash tree (Fraxinus excelsior) (Flowerdew and Gardner 1978) and grass (Macdonald 2001).

Plant Foods: leaves; seeds, grains, and nuts; fruit

Foraging Behavior: stores or caches food

Primary Diet: herbivore (Folivore , Frugivore , Granivore )

Bank voles are important as a prey base for many small avian and mammalian predators and snakes. They are often abundant and can form the main component of the diet of these predators. They may also help in recycling and redistributing nutrients in the ecosystems in which they live through herbivory.

Many small predators rely on bank voles as prey. Bank voles partially escape predation by remaining under cover in underground tunnels or runways in grass and vegetation. I is thought that avian predators use the ultraviolet reflections of scent marks to locate their prey (Koivula et al. 1999).

Known Predators:

• least weasels (Mustela nivalis)
• stoats (Mustela erminea)
• European minks (Mustela lutreola)
• red foxes (Vulpes vulpes)
• tawny owls (Strix aluco)
• rough-legged hawks (Buteo lagopus)
• common kestrels (Falco tinnunculus)

Clethrionomys glareolus is prey of:
Buteo lagopus
Falco tinnunculus
Mustela vison
Mustela nivalis
Mustela erminea
Vulpes vulpes
Strix aluco

This list may not be complete but is based on published studies.

Animal / parasite / ectoparasite / blood sucker
Amalaraeus penicilliger mustelae sucks the blood of Clethrionomys glareolus

In Great Britain and/or Ireland:
Animal / parasite / endoparasite
Babesia microti endoparasitises red blood cells of Clethrionomys glareolus

Animal / parasite / endoparasite
Capillaria hepatica endoparasitises patchily yellow liver of Clethrionomys glareolus

Animal / parasite / endoparasite
Capillaria muris sylvatici endoparasitises intestine of Clethrionomys glareolus

Animal / parasite / endoparasite
tapeworm of Catenotaenia lobata endoparasitises small intestine of Clethrionomys glareolus

Animal / parasite / endoparasite
tapeworm of Catenotaenia pusilla endoparasitises small intestine (middle part) of Clethrionomys glareolus

Animal / parasite / endoparasite
fluke of Corrigia vitta endoparasitises pancreas (interlobary canals) of Clethrionomys glareolus

Animal / parasite / endoparasite
Eimeria endoparasitises rectum of Clethrionomys glareolus

Animal / rests in
Entamoeba muris rests inside large intestine of Clethrionomys glareolus

Animal / parasite / endoparasite
Frenkelia glareoli endoparasitises brain of Clethrionomys glareolus

Animal / parasite / endoparasite
Giardia microti endoparasitises small intestine of Clethrionomys glareolus

Animal / parasite / endoparasite
schizont of Hepatozoon erhardovae endoparasitises lung of Clethrionomys glareolus

Animal / parasite / endoparasite
Hexamita muris endoparasitises caecum of Clethrionomys glareolus

Animal / parasite / ectoparasite / blood sucker
Hystrichopsylla talpae talpae sucks the blood of Clethrionomys glareolus
Other: minor host/prey

Animal / parasite / ectoparasite / blood sucker
Ixodes trianguliceps sucks the blood of skin of Clethrionomys glareolus

Animal / parasite / endoparasite
spirally coiled worm of Nematospiroides dubius endoparasitises duodenum of Clethrionomys glareolus

Animal / parasite / endoparasite
preadult of Pelodera strongyloides endoparasitises tears of Clethrionomys glareolus
Other: major host/prey

Animal / rests in
posterior intestine of Syphacia obvelata rests inside Clethrionomys glareolus

Animal / parasite / endoparasite
Cystocercus larva of Taenia taeniaeformis endoparasitises liver of Clethrionomys glareolus

Animal / parasite / endoparasite
Trichomonas muris endoparasitises caecum of Clethrionomys glareolus

Animal / parasite / endoparasite
Trypanosoma evotomys endoparasitises blood plasma of Clethrionomys glareolus
Other: sole host/prey

The lifespan of M. glareolus is very short. Average lifespan is 0.5-2 years, with most individuals not lasting more than one breeding season (Macdonald 2001; Ostfeld 1985). Bank voles mature quickly with females maturing at 2-3 weeks and males maturing at 6-8 weeks (Macdonald 2001).

Range lifespan

Status: wild: 0.5 to 2 years.

Typical lifespan

Status: wild: 0.5 to 2 years.

Maximum longevity: 4.9 years (captivity)

The mating system of M. glareolus can be described as polygamous (Macdonald 2001), and possibly promiscuous (Horne and Ylonen 1998). While females defend territories that may overlap with other females, males defend larger territories that overlap with the territories of several females. Females appear to prefer dominant males and may affect which males get the chance to mate by running away from subordinate males (Horne and Ylonen 1998). As parturition nears, females become more aggressive and each female's territory decreases in size. The home range becomes smaller and the central ranges of different territories become farther from each other (Koskela et al. 1997).

Mating System: polygynous ; polygynandrous (promiscuous)

The estrous cycle of M. glareolus lasts four days (Oksanen et al. 1999). The breeding season is from late April to September (Oksanen et al. 2001). Copulation is characterized by a series of intromissions followed by ejaculation (Horne and Ylonen 1996).  Gestation lasts from 17 days with optimal nutrition, to 24 days if the female becomes pregnant while lactating during postpartum estrus (Macdonald 2001; Koskela et al. 1998). The average gestation length is 21 days (Macdonald 2001). From 1 to 10 pups are born per litter with approximately 4 litters born per breeding season (Macdonald 2001; Oksanen et al. 2001). The average number of pups per litter is 4-8 (Oksanen et al. 2001). Pups weigh 1-10g at birth, which makes up a total of 22-28% of the female’s weight. During pregnancy and lactation, females require 30-130% more energy (Ostfeld 1985). Infanticide occurs in males and females. Females will kill the pups of their female neighbors and males will kill pups as a mating tactic (Koskela et al. 1998; Koskela et al. 1997; Horne and Ylonen 1996).

Breeding season: Breeding occurs from April to September.

Range number of offspring: 1 to 10.

Average number of offspring: 4-8.

Range gestation period: 17 to 24 days.

Average gestation period: 21 days.

Range weaning age: 20 to 25 days.

Range age at sexual or reproductive maturity (female): 2 to 8 weeks.

Average age at sexual or reproductive maturity (female): 3-6 weeks.

Range age at sexual or reproductive maturity (male): 2 to 8 weeks.

Average age at sexual or reproductive maturity (male): 3-6 weeks.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous

Pups are born blind and helpless in an underground nest lined with grass and other vegetation. The female is the sole provider of parental care (Macdonald 2001). The pups are weaned at the age of 20-25 days (Macdonald 2001; Oksanen et al. 2001; Oksanen et al. 1999; Horne and Ylonen 1998).

Parental Investment: altricial ; female parental care

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 251
Species With Barcodes: 1

Bank voles are widely distributed and often abundant, they are not threatened.

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: NNA - Not Applicable

Rounded Global Status Rank: G5 - Secure

Not legally protected in the UK. No conservation designations (3).

Population

Population Trend

Major Threats

Where they occur in close proximity to roads, bank voles may be at risk from lead exposure. In agricultural areas, pesticide drift, and exposure to molluscicides and rodenticides may all pose threats. The fragmentation of woodlands, removal of hedgerows and overgrazing of herbaceous ground cover by deer reduce the chances of bank voles persisting in an area (4).

Conservation Actions

There is no conservation action targeted at this species.

Myodes glareolus have been found to spread hantavirus. In temperate climates, they are also crop pests (Macdonald 2001).

Humans benefit from bank voles through their beneficial ecosystem roles.