Bank Vole

The bank vole (Myodes glareolus) is a small rodent belonging to the family Cricetidae, order Rodentia. It occupies a broad Palearctic distribution, extending from the British Isles across continental Europe to western Siberia and the Ural Mountains. Within this range the species inhabits deciduous and mixed woodlands, dense undergrowth, hedgerows, meadow edges, and damp marshy areas where leaf litter and moss provide cover. Adults measure 7–10 cm in head‑body length, possess a short, hair‑less tail of 3–5 cm, and weigh between 18 and 35 g. The dorsal pelage is brown to reddish‑brown with a paler ventral side, a coloration that offers camouflage among fallen leaves and grasses. Bank voles are primarily terrestrial but are capable of brief arboreal forays. They play a crucial role in forest ecosystems as seed dispersers and as prey for a variety of raptors, mustelids, and carnivorous mammals. The International Union for Conservation of Nature (IUCN) classifies the species as Least Concern due to its wide distribution and large, stable populations, although local declines have been recorded where intensive agriculture or forest fragmentation reduces suitable habitat.

Bank voles are crepuscular to nocturnal, emerging at dusk to forage and retreat to burrows before dawn. They construct shallow, branching tunnel systems lined with grass and shredded plant material, often nesting in concealed spots such as under logs, in dense vegetation, or within abandoned mouse burrows. Socially, they are largely solitary outside the breeding season, with individuals maintaining overlapping home ranges of 0.2–0.5 ha. Males patrol larger territories that may intersect several female ranges, using scent marking from cheek glands and urine to communicate reproductive status and deter rivals. Vocalizations are limited to soft squeaks and ultrasonic calls, while foot‑drumming and tail‑thumping serve as alarm signals when predators are detected. Seasonal changes influence activity patterns; during winter voles reduce metabolic rate and may enter short torpor bouts to conserve energy.

Bank voles are primarily herbivorous, feeding on a diverse array of plant material. Their diet consists of seeds, grasses, herbaceous shoots, buds, and the fruits of shrubs such as bilberry (Vaccinium myrtillus) and raspberry (Rubus idaeus). In autumn they heavily consume fallen acorns and beech mast, which provide essential lipids for winter survival. In addition to plant matter, bank voles opportunistically ingest insects, spiders, and other small invertebrates, especially when protein demand is high during lactation. Seasonal fluctuations drive dietary shifts: spring diets are rich in young leaves and buds, summer diets emphasize grasses and herbaceous flowers, while winter diets rely on stored seeds and bark. An adult vole consumes roughly 3–5 g of food daily, equivalent to 10–15 % of its body mass. Foraging occurs primarily on the ground, but individuals will climb low vegetation to access seeds and buds. Food caching is common; voles transport seeds to hidden caches within their burrow system to buffer against periods of scarcity.

Bank voles reach sexual maturity at 4–6 weeks for females and 6–8 weeks for males under favorable conditions. Breeding commences in early spring (April–May) and can continue through late summer, with a peak in June. Females are capable of producing up to three litters per year, each after a gestation of 21–23 days. Litter size averages 4–6 pups, though litters of up to eight have been recorded in resource‑rich habitats. Newborns are altricial, hairless and blind, and are nursed for approximately three weeks before weaning. Maternal care is intensive; the mother builds a nest of dry grass and fur, and she remains with the litter for the first two weeks, defending them against conspecifics and predators. After weaning, juveniles disperse to establish their own territories, a process that reduces inbreeding and promotes gene flow across populations.

The IUCN lists the bank vole as Least Concern, reflecting its extensive range and large overall population, estimated at several million individuals across Europe. Nevertheless, localized threats have caused declines in certain regions. Intensive agricultural conversion removes hedgerows and grassland mosaics that provide essential cover and foraging grounds. Forest management practices that eliminate understory vegetation and deadwood reduce habitat complexity, making voles more vulnerable to predation. Pesticide exposure can diminish invertebrate prey and directly affect vole health. Climate change poses a longer‑term risk by altering the phenology of seed production and increasing the frequency of extreme winter events, which can lead to higher mortality. Conservation measures focus on maintaining heterogeneous landscapes, preserving hedgerow networks, and promoting sustainable forestry that retains leaf litter and understory layers. Monitoring programs in the United Kingdom and Scandinavia have documented stable or modestly increasing trends where such habitat features are protected, underscoring the importance of landscape connectivity for the species’ resilience.

• Bank voles can produce up to three litters per year, allowing rapid population growth.
• They are capable of short torpor bouts in winter, lowering body temperature to conserve energy.
• Their cheek glands secrete a musky scent used for territory marking and mate attraction.
• Bank voles play a key role in seed dispersal, especially for forest understory plants.
• They can survive on as little as 10 % of their body weight in food each day.