Outdoor cousins of the House Mouse, which tend to move indoors in the winter seeking their creature comforts.
It's important to understand that pest management professionals will avoid controlling field mice unless they are presenting a public health risk.
Field mice are small mammals of the order Rodentia.
You can find out more about mice, their biology and behaviour, and how to control them in our ultimate A-Z guide.
In this guide
The dangers: why we control mice
Although mice are often considered to be cute by some people, they are a public health pest and can cause serious harm.
Mice have been known to spread nasty diseases - such as Salmonella and Listeria - to humans through their urine, droppings and bedding.
Mice have a need to mark their territory with their urine and due to their sporadic eating habits, build nests near food sources. This puts anyone with an infestation at risk of food poisoning.
As they scurry around, they carry dirt and bacteria with them, transferring it to your counter tops, cabinets, pantry and anywhere else they travel.
These nibbling nuisances can also cause a lot of property damage, due to their compulsive need to gnaw to maintain their teeth at a constant length.
Electric cables, water and gas pipes, packaging and woodwork may all be seriously damaged by mice - many instances of electrical fires and floods have been attributed to them.
Why are field mice more common in winter?
As the weather gets colder, those field mice currently surviving outdoors will look for warmer places to nest and begin to move indoors.
They are highly adaptable and won’t hesitate to take advantage of a cosy human structure during the winter months.
Food is also an issue - they begin to scavenge closer to humans, as their own sources are no longer plentiful.
Appearance
Field mice
A field mouse has sandy brown fur with a lighter underside.
As it mainly lives outdoors, it has bigger eyes and ears than a house mouse. This is an adaptation to avoid predation.
Field mice also have long tails, making them quite agile climbers.
Juveniles are greyer overall, still with larger ears, hind feet and tails than house mice.
House mice
In comparison, the house mouse has a typical mouse profile: small feet with smaller eyes and thinly-haired ears, and a pointed snout with thin whiskers.
Their body length ranges between 60-90mm, and the tail generally equals the length of its body, adding another 90mm.
They weigh less than 25g, and their fur colour is uniformly light brown and grey, right down to the tail which has sparse hairs on it.
And keep those pegs handy - they have a really distinctive, strong smell so you’ll know if you have a large infestation of these unwanted guests.
How to prevent field mice
Prevention is better than cure, so let’s take a look at how we can accomplish that.
Field mice only need a gap of 5mm to gain entry (roughly the diameter of the eraser end of a pencil).
You will need to search for any potential entry points and seal these up with wire wool embedded in quick-setting cement.
You should focus on low level gaps first as these are the most likely areas for field mice to enter. You can then consider any higher up vents or gaps.
Check around pipes and windows, and double check the basement.
You should focus on low level gaps first as these are the most likely areas for field mice to enter.
Proofing all means of entry as much as possible will help to prevent an infestation.
Other steps you should take are:
- Remove potential nesting sites by keeping gardens clean and tidy, cutting back overgrown areas and clearing any piles of wood/debris
- Cover any household waste where mice can get access to it, close dustbin lids and cover compost heaps
- Store food in airtight containers and make sure any food debris is cleaned up straight away
- Install door sweeps or door brush strip on exterior doors, if the gap is larger than 4mm.
Good hygiene practices won’t eliminate a mouse problem, but poor practices will attract them.
Getting rid of field mice
Professional pest control
For any mouse infestation, we would always recommend contacting a professional pest control company.
They are trained in mouse control and professionals are able to take control of situations efficiently.
Field mice can only be controlled by using non-chemical means with tools such as good root cause analysis, hygiene and housekeeping, proofing and then maybe a trapping programme.
Professional pest controllers will take an integrated pest management (IPM) approach to tackle your infestation.
A pest professional will have access to monitoring equipment, which they will use to confirm entry points into your property and the infestation's size and to track the mouse to its harbourage (nest).
They can then recommend a proofing strategy and decide on the best course of action in terms of control.
Finding a pest controller to get rid of field mice
A BPCA member company will be able to treat infestations quickly and safely.
They can help minimise pest activity with a range of techniques and have the technical knowledge and experience to apply products in an efficient manner, while minimising risk to the environment and non target species.
All BPCA members employ qualified technicians who frequently update their knowledge.
We audit all our members to the British and European Standard for Pest Management, BS EN 16636.
You can find a BPCA member, local to you, using our Find a pest controller tool.
Source: A-Z