- Size
- Body 7–9 cm, plus a tail as long again
- Droppings
- 3–6 mm, like grains of rice
- Active
- Mostly at night
- Peak season
- Autumn and winter
The catch is speed. A mouse can squeeze through a gap about the width of a pencil, and a pair can become dozens within a few months. Act on the first signs, not the tenth.
Signs of mice
- Droppings 3–6 mm long with pointed ends, scattered in cupboards, drawers and along skirting
- A light, quick pitter-patter in walls, ceilings or under floors at night
- Nibbled food packets, especially cereals, biscuits and pet food
- Small nests of shredded paper, fabric or insulation in hidden corners
- Greasy dark smear marks along skirting boards and around holes
- A stale, musky smell in cupboards or under the kitchen units
How to be sure
Mice have large ears, a pointed snout and a long, thin tail. Rats are far heavier, with small ears, a blunt snout and a thick tail. The quickest way to tell is droppings: mouse droppings are grain-of-rice sized, rat droppings are closer to a large sultana.
Bat droppings are a similar size to mouse droppings but crumble to dust when crushed. If you're finding them in the loft, check before you do anything.
What you can do yourself
- Use several snap traps rather than one. Set them against walls at right angles, with the trigger end touching the wall, where droppings are thickest.
- Bait with a pea-sized dab of peanut butter or chocolate spread. Cheese is less effective than its reputation.
- Check traps every day, wearing disposable gloves. Reset and move any that haven't caught anything after three days.
- Seal gaps around pipes, cables and boiler flues with wire wool packed tight, then filler or a rodent-proof sealant over the top.
- Fit brush strips to the bottom of external doors and check air bricks have intact mesh.
- Move dry food, pet food and bird seed into sealed containers.
- Keep trapping for two to three weeks after your last catch.
Call a professional if
- You're still catching mice or finding fresh droppings after two to three weeks
- There are droppings in several rooms or on more than one floor
- You've found chewed wiring
- You live in a flat or terrace with shared voids and the problem keeps coming back
- Someone in the household is vulnerable, or you run a food business from home
The law: Glue traps are banned in Wales and Scotland. In England, using one on rodents without a Natural England licence is an offence, even though they are still sold. We never recommend them.
Safety: Mouse droppings and urine can carry salmonella and other bacteria. Wear gloves, don't sweep dry droppings, and disinfect surfaces before wiping up.
Keeping them out
- Proof gaps of 6 mm or more around pipes, cables and under doors
- Keep food sealed and wipe up crumbs, especially under appliances
- Don't leave pet food out overnight
- Clear clutter from lofts, garages and under-stairs cupboards
- Check new deliveries of stored goods like logs or garden furniture before bringing them in
Kit that helps
- Snap traps, several
- Enclosed trap stations if you have children or pets
- Wire wool
- Rodent-proof filler or sealant
- Door brush strips
- Airtight food storage
- Disposable gloves
Product types only. We'll only ever point you to things we'd use ourselves.
Questions people ask
Do ultrasonic plug-in repellers work?
The evidence is weak. Mice often get used to the sound within days, and it doesn't pass through walls or furniture. They won't solve an established problem.
Should I use poison for mice?
We suggest traps first inside the home. A poisoned mouse can die under the floor or in a wall, causing a smell for weeks. If you do use poison, only use amateur-use products inside tamper-resistant bait stations, well away from children and pets.
Will mice go away on their own?
Rarely. A warm house with food is exactly what they're looking for. Without trapping and blocking how they got in, numbers usually grow.
I've seen one mouse. Is that a problem?
Where there's one, there are usually more. Mice are mostly active when you're not watching, so a sighting usually means an established group.
What's the best bait for mouse traps?
Something sticky and smelly that they can't snatch: peanut butter, chocolate spread or a little hazelnut paste. Use a tiny amount so they have to work at the trigger.