Common Vole, Microtus arvalis
The common vole (Microtus arvalis) is native to Eurasia, with a very large range stretching across many areas. Its preferred habitat includes all areas besides densely forested areas. It will inhabit agricultural lands, and as a result will end up eating the crops found there, although it prefers grass.
The common vole varies slightly in size between sexes, with males weighing an average of 1.7 ounces and females weighing 1.4 ounces if not pregnant. It will inhabit home ranges of up to .3 acres, depending on the sex. Within these home ranges are nests, dug into the ground between 11.8 and 15.7 inches deep, which are used for resting, rearing young, and storing food. Runways are used for optimum protection while moving about above ground, and the voles rarely leave the safety of these paths.
The mating season of the common vole occurs between the months of March and October, and females are able to give birth up to three times in this period. The lifespan of this species is short, only 4.5 months on average, so the last litter is typically the only to survive. Each litter can contain between three to eight young. Weaning occurs at around twenty days after birth, but mating can occur at only thirteen days.
The population densities of this species vary from season to season, with females often outnumbering the males. This causes intense competition for males, which leads to higher death rates. When numbers are high, females may cease reproducing in order to conserve space and food. Even if population density is high, home ranges do not overlap. Because common voles are polygynous, males often leave temporary home ranges in order to have more mating opportunities, and it is also thought that males will leave their birth areas when populations become too large.
The common vole is a vital food source to many predators, including bird like the tawny owl, barn owl, buzzard, and kestrel in central Europe. Its ground predators include the adder, weasel, boar, and fox. Population numbers are typically high, and because there are no main threats to the common vole, it appears on the IUCN Red List with a conservation status of “Least Concern”.
Image Caption: Common Vole, Microtus arvalis. Credit: Dieter TD/Wikipedia (CC BY-SA 3.0)