Mice Advice

What are the signs of infestation?

There are a number of signs to look out for and if found, may indicate mouse activity.

Mice droppings

Droppings are often black, rod shaped and 3-6mm long. Fresh droppings will be soft and moist. Each mouse can leave approximately 80 droppings per day. Common places to find mouse droppings are under the kitchen sink, around central heating boilers and in roof spaces.


These are dark grey marks left on surfaces by repeated contact with oils in the mouse fur.


Sometimes nests can be found indoors for example in lofts, under floorboards or in airing cupboards.


Mice gnaw continually on materials such as wood, carpets, paper, pipe cables and furniture. Check for damage to foodstuffs in cupboards.

Why must mice be controlled?

In addition to the damage caused through gnawing, mice have been known to spread diseases such as salmonella and listeria, which lead to food poisoning and stomach upsets.

How can I prevent a mouse infestation?

Householders can assist in preventing mouse infestation by taking a number of simple precautions.

  • Keep your home in good repair. Mice only need a gap the diameter of a pencil to gain entry.
  • Remove potential nesting sites by keeping yards and gardens clean and tidy, and by cutting back overgrown areas.
  • Seal gaps around heating and water pipes.
  • Ventilation bricks and slots should already have a fine wire mesh incorporated. If this is worn, replace externally with 3.15mm insect mesh.
  • Do not leave household waste where mice can get access to it, close dustbin lids and composters and do not feed wild birds to excess – you may be feeding mice as well.

What do they look like?

The most common mouse found in buildings is the house mouse, weighing less than 25g. The fur colour varies between light brown and grey. Body length ranges between 60-90mm and the tail can add an additional 100mm. Mice have an acute sense of hearing, frequently using ultrasound to communicate, and are particularly sensitive to any sudden noise.

Where do they live?

Mice live in nests that they build out of cloth, wool and paper. Nests are often built inside houses, in places such as roof spaces, under floors or in wall cavities, and wherever there is access to a good source of food, especially during the winter. Mice can squeeze through cracks as small as 5mm but mouse holes are normally 20-30mm in diameter. Mice are mainly active at night and can often be heard running about as they search for food.

What do they eat?

Their favourite foods are cereal products, although they will eat almost anything. Most of the damage they do is by gnawing and ripping open packets. They also spoil food with urine and droppings. Mice will gnaw their way through wood to get sources of food.

How can I get rid of mice?

It is important to get rid of mice quickly, as house mice reproduce rapidly. It is possible to carry this work out yourself however, a professional pest control expert will always have more technical expertise and access to rodenticides that are not available over the counter.

If you decide to carry out the work yourself there are two options, poison or break-back traps.

Mouse poison (rodenticide) can be bought from most hardware stores and most garden centres. Put the poison in a safe and secure place out of reach of children and pets and ALWAYS wash your hands after use. Rodenticide can take 4-12 days to take effect. This may result in a localised foul smell due to presence of carcasses.

Break-back traps may be set and these should be placed next to walls where mice tend to travel. The trap should be baited with chocolate, biscuit or cereal. Use several traps and examine them daily, removing dead mice as soon as they are discovered. All traps should be handled with care.

Please contact us if you require any assistance.

Warning: Use biocides safely. Always read the label and product information before use.

Information provided by Killgerm.