History of... Field Vole

Name:
Field Vole

Scientific Name:
Microtus agrestis

Family:
Cricetidae

Conservation Status:
Least Concern

Habitation:
Overgrown fields, moorlands, young forest plantations, and roadside verges.

Global Location:
United Kingdom, Ireland, Spain and Portugal through forested habitat across most of Europe, Russia and Northern China.

The field vole, also known as the short-tailed vole, is one of the most common and ecologically vital small mammals found across Europe and mainland Britain.

First Discovered:
They were classified by the Swedish scientist Carl Linnaeus in 1761. The name agrestis originates from Latin, meaning "belonging to the fields" or "wild."

Appearance:
At first glance a field vole looks like a mouse but it has several differences:
The body is heavy, stocky, and rounded, measuring between 9 and 12.5 cm in length. The fur is shaggy, grey brown fur on its back, with an off white or pale grey belly. The face is short with a rounded muzzle with small dark eyes. The ears are very short and covered in thick fur. The tail is short, about 3 to 4 cm long, which is one third of the body length.

Behaviour and Social Structure:
Field voles are solitary animals and are active throughout both day and night, alternating between short bursts of foraging and resting. They are poor climbers and spend their entire lives on or just under the ground.

To move around safely, they chew grass to form an intricate maze of surface runways hidden beneath the vegetation. They are fiercely territorial and mark these paths with urine. While this warns away rival voles, it comes with danger as their urine glows under ultraviolet light. This creates a bright neon trail that birds of prey can track from the sky.

Diet:
Field voles are herbivores. Their main food is grass stems and leaves. During winter when grass is scarce they eat roots, bulbs, moss, and the bark of young trees. As grass has low nutritional value, a vole must eat constantly as they can starve in less than 14 hours without food.

Breeding:
The breeding season lasts from March to October. A single female can produce between 3 to 7 litters a year. Each litter typically contains 4 to 6 pups, which are born blind and hairless inside a woven ball of shredded grass. Pups are weaned in just 12 to 14 days. Females reach maturity at just 28 days old, meaning a vole born in the spring can have her own babies before the summer ends.

Threats to Population:
There is an estimated UK population of roughly 60 to 75 million field voles, the biggest threat to an individual field vole is hunting. They have an incredibly short lifespan in the wild. usually less than a year, because they are the primary food source for barn owls, kestrels, weasels, stoats, foxes, and domestic cats. They face threats from habitat loss from farming, livestock overgrazing and urban development.

History:
Field voles colonised northern regions of Europe following the retreat of the glaciers at the end of the last Ice Age. Every 3 to 5 years their populations have boom and bust cycles. A boom sees thousands of voles in a single hectare of land, causing minor plagues that damaged forestry and crops. Nature balances this out by rising predator numbers immediately after a vole boom which reduces the vole population again.