Signs of Mice at Home and Ways to Protect Against Them

Mice are nocturnal, cautious and fast-breeding animals. A pair of house mice can produce 40-60 young a year, so acting on the first sign is the only way to stop them before they spread. Below you will find the most common signs and ways to protect yourself.

Signs of mice

• Droppings: Rice-grain-sized, dark, pointed droppings; in kitchen drawers, cupboard corners and behind worktops.
• Gnaw marks: On food packaging, cable sheaths, the bottom edges of wooden doors and plastic pipes.
• Night noises: Scratching and scrabbling between walls and ceilings.
• Greasy marks: Dark, oily smears at wall bases along mouse runs.
• Nesting material: Nests made of paper, fabric and insulation fragments.

Why does it matter?

Rodents do not only eat food; they can spread diseases such as leptospirosis, salmonellosis and hantavirus through urine and droppings, and gnaw cables, creating fire risk. In allergic and asthmatic people, dropping dust can trigger respiratory complaints.

How do they get in?

A house mouse can squeeze through a 1 cm gap and a rat through 2 cm. Entry routes include pipe penetrations, gaps under external doors, ventilation grilles, chimneys and drain connections. Basements, attics and pantries are the most common nesting places.

Trap or bait?

Both have their place. If there are children and pets at home, a locked bait station or a mechanical trap is the safe option. Poisoned bait left in the open poses a serious danger especially to small children and animals; leave such treatment only to a trained technician. Glue boards help in short-term and mild problems, but the animal suffers and can cause odour.

Seven steps for lasting protection

1. Seal entry gaps with steel wool and metal mesh (mice cannot gnaw steel wool).
2. Fit brush strips or aluminium thresholds under doors.
3. Store food in glass or rigid plastic containers.
4. Keep rubbish in a lidded bin and take it out every evening.
5. Keep woodpiles and stored items in the garden away from walls.
6. Do not leave bird seed and pet food out overnight.
7. Check the basement and attic twice a year.

When to call an expert

If you see more than one sign, hear noises inside walls or the problem affects the whole building, professional help is essential. We identify entry routes, place stations and deliver a follow-up report with a check visit after 14 days.

Pet and child safety

In any home where poisoned bait is used, bait stations must be locked and their placement recorded on a plan. In case of accidental contact or swallowing, call the National Poison Information Centre on 114.