Mice - Advice for identifying and controlling

What do they look like?

Domestic mouse

The house mouse is usually a uniform colour, although sometimes the lower half may be a slightly lighter shade.  In some cases, the grey may be quite dark.  Adults range from about 7 to 9cm in length, not including the tail.

Wood mouse

The wood mouse has an orange-brown back and white underparts, with a clear dividing line between the two.  The adult is larger than the house mouse and ranges from 8 to 13cm in length, not including the tail.

How do you spot them?

Possible indications include:

• Gnawing - smaller teeth marks than rats and can be evident in almost anything, such as bars of soap.  Shredded paper may be found and damage to packaging may be evident
• Droppings - small, black and irregular, approximately 2mm long.  One mouse can produce up to 60-100 droppings per day
• Smell - a mousy stale type odour can be present, especially if they become established
• Sightings - mice may be seen during the day although their most active period is at nighttime
• Tracks - some tracking may be seen although they are not as easily seen as rat tracks

How do they affect humans?

Mice have a compulsive need to gnaw in order to keep their incisor teeth worn down.  Electric cables, water and gas pipes, packaging and woodwork may all be seriously damaged by mice.  Mice are able to live in almost any available space.  The average mouse deposits 70 droppings in 24 hours and urinates frequently to mark its territory.  They carry a wide range of diseases which can be passed on to humans, either by directly contaminating food with droppings and urine, or by contaminating surfaces.

The Life Cycle

Mice become sexually mature in eight to ten weeks, and a pair may produce eight litters, each of sixteen young, in a year.  Mice nibble at many sources of food rather than taking repeated meals from any one item.  They do not need water to drink as they normally obtain sufficient moisture from their food.

The mouse is very inquisitive and will soon investigate anything in its surroundings, they are very good climbers and very agile.  They can squeeze through extremely small openings, living and breeding under floors, in cavity walls, ceiling voids and behind skirting boards.  They will often enter domestic properties in the late autumn when food sources are low and the temperature drops.

How do you control them?

• Keep food in mouse-proof containers
• Sweep up any spillages as they occur
• Do not leave pet food lying around
• Clean up under work units and other areas where food residues can accumulate
• Keep outbuildings clear of clutter and store animal feed properly
• Do not assume that a cat will prevent mice.  Cats can sometimes be the culprits, bringing in live mice and dropping/losing them in the house
• Proof or seal any holes around the building in which a pencil can be fitted if the hole is not supposed to be there.  Fine wire gauze or sealant should be suitable.
• Mice will leave urine trails with a strong scent.  Once a mouse problem is cleared in the house, a strong smelling disinfectant should be used to clean surfaces and destroy scent trails were possible. 
• If a regular problem with mice is encountered, any ivy or close growing plant to the house may need to be considered to be cut back

Treatment

North Shropshire District Council provides treatment for mice free of charge in domestic properties.