The field mouse, more correctly known as the wood mouse (Apodemus sylvaticus), is one of the UK's most widespread wild mammals. They usually live in fields, woodlands and hedgerows. Despite this, they sometimes enter gardens, sheds, garages and even vehicles in search of food and shelter. Understanding where field mice live, what they eat and how they breed can help homeowners prevent infestations.

Where Do Field Mice Live?

Field mice are commonly found in gardens. Those with dense vegetation, compost heaps, sheds and hedgerows are particularly attractive. They prefer habitats that provide plenty of cover from predators and easy access to food.

Other places field mice live include;

Grassland
Hedgerows
Farms
Wood
Heathland
Moors

You are more likely to find them in woodlands in the winter as these give them better shelter from the elements. Field mice live in burrows under the ground which they dig to keep their families warm and safe from predators. As the burrows are very small, predators cannot reach them. They use plants to make nests in the burrows, keeping them warm.

When the weather becomes colder they are more likely to move into human building such as garages and outbuildings. They can damage cars and other property when finding food and building nests. This article on our blog has some ideas on how you can keep them at bay; https://www.hammertechltd.com/blog/keep-rats-away-the-ultimate-guide-to-rat-protection-for-cars-and-rvs

What is their Distribution?

They are native to the UK and in Europe range as far north as Scandinavia and east to the Ukraine. In the UK they occur throughout England, Scotland, Wales and much of Ireland, making them one of Britain's most common wild rodents. They are also commonly found on several of the islands in the Mediterranean, as well as northwest Africa.

What do Field Mice Eat?

They like to eat berries and seeds which they store underground. They predominantly eat seeds from trees such as sycamore, oak, hawthorn, ash, lime and beech. As they are omnivores they also eat nuts, fungi and insects. They harvest these in the autumn and save them for the winter when food is scarce. They store them in their burrows which is a great way for seeds to be dispersed as many of them will grow into trees before they are eaten.

Although wild seeds and berries form most of their diet, field mice readily take bird seed, pet food and food waste left around homes. This is one reason they are attracted to gardens and outbuildings. Read more on how to rodent proof you house and garage here; https://www.hammertechltd.com/blog/diy-rodent-proofing-for-buildings-and-garages-a-practical-guide

Breeding Behaviour

Field mice will often mate on multiple occasions and with multiple mates. This can result in a litter containing offspring from more than one father. Females can have up to an astonishing six litters a year. Each litter contains between four and eight pups; this is the name for a baby. They have a very short gestation period of only, 23-26 days. This means that one breeding pair can have up to 48 babies every year! They also reach sexual maturity very quickly in just 4 to 8 weeks. This means that if each baby continues to reproduce at the same rate and none are eaten or die. Under ideal conditions, the descendants of a single breeding pair can number in the thousands within a year. This is because young mice mature and begin breeding rapidly. Their breeding season is from around March to October.

Which Animals Eat Field Mice?

Predators include;

Owls
Kestrels
Eagles
Falcons
Buzzards
Foxes
Cats
Dogs
Badgers
Snakes
Weasels

Interesting Field Mouse Facts

A field mouse can squeeze through a gap only 6–7 mm wide—about the diameter of a pencil.
They use whiskers to navigate in complete darkness.
They have an excellent sense of smell and hearing.
They can jump surprisingly high for their size.
They store food underground for winter.
They enter a short period of torpor rather than true hibernation.
They can shed the end of their tails to escape a predator, although it may not regrow.
Instead of hibernating they go into a state called torpor. This involves a reduced body temperature and metabolic rate. This is usually shorter than hibernation and is a lighter state.
Their babies are called pups.
Wild mice can carry diseases and parasites. In rare cases, rodents have been associated with hantaviruses, although the risk to the general public in the UK is considered very low. Avoid contact with rodent droppings and follow cleaning advice when dealing with an infestation.
In winter they may eat hibernating bats but this has not been proven.
They sometimes use twigs and leaves as markers to help them navigate when they are looking for food.
A breeding pair can create more than 3000 offspring in a year.

Conclusion

Field mice play an important role in the British countryside. Unfortunately they can become a nuisance when they move into gardens, garages and vehicles. Their ability to squeeze through tiny gaps and reproduce rapidly causes problems. However, this means early prevention is far easier than dealing with a large infestation. If you're experiencing rodent problems around your home or car, simple measures can help keep mice away before damage occurs.

References

https://www.wildlifetrusts.org/wildlife-explorer/mammals/wood-mouse

https://en.wikipedia.org/wiki/Wood_mouse

By Dr Toby Bateson for Hammer Technologies Ltd