Common vole

The common vole (Microtus arvalis) is a widespread rodent in Eurasia, excluding the British Isles where it is replaced by Microtus agrestis. It inhabits open areas like meadows and heaths as primary habitats and agricultural fields as secondary habitats, particularly shallow sloped ones. In agricultural settings, it feeds on crops, leading to faster reproduction compared to natural environments. Reproduction involves females giving birth to 3-8 juveniles after a 16-24 day pregnancy. Juveniles can be impregnated from the 13th day post-birth, allowing for early reproduction. Females typically have three reproductive cycles annually, starting in March and ending in October. The average lifespan is 4.5 months, with most dying after autumnal reproduction, though some young survive winter. Sex ratios at birth are equal but skew female-heavy as animals mature or population density increases, reaching up to 4:1 favoring females. This leads to intense male competition for mates, increasing mortality and dispersal rates. Population densities vary significantly (100-2000 individuals per hectare) over 3-5 year cycles, influenced by reduced reproduction at higher densities. Common voles construct aboveground runways and underground nests up to 40cm deep for storage and young rearing. Nests can be shared by up to five females without territorial overlap. Males are polygynous, often acting as floaters between female territories. Home ranges are larger for males (1200-1500m²) than females (300-400m²), both reducing range size with higher density. Male dispersal is driven by mate competition. Predators include birds like buzzards and owls, and ground predators such as weasels and foxes. The species regulates ...