Can you hear faint scratching behind the skirting boards at night, or have you found small black droppings in a kitchen cupboard? Chances are you have mice in the house. In autumn, when temperatures drop and food gets scarce outdoors, the house mouse looks for somewhere warm with food close at hand, and your home is ideal. Here’s how to recognise the signs, how to catch them safely and, above all, how to stop more getting in, even if you have a dog or a cat.
Do you have mice in the house? These are the signs
- Droppings: black, about the size of a grain of rice, often along walls, inside cupboards and behind the fridge.
- Gnaw marks on packaging, cables, skirting boards or insulation.
- Noises and scratching, especially at dusk and during the night, in ceilings, cavity walls or the meter cupboard.
- A strong, stale smell, a bit like ammonia, once they’ve been around for a while.
- Nests made of shredded paper, fabric or insulation in warm, quiet corners.
If you see one mouse, there are usually more. They breed very quickly, so the sooner you act, the better.
How do mice get in?
A house mouse can squeeze through a gap the width of a pencil. The most common entry points are:
- gaps under external doors and around door frames;
- holes around heating, gas and waste pipes;
- air vents with no mesh;
- the garage, the storeroom and the crawl space under the floor;
- a cat flap that is always left open.
How to catch mice safely
- Choose a snap trap or a live-catch trap. A classic snap trap works fast. If you’d rather not kill them, use a cage trap and check it morning and evening. Release the mouse well away from your home, or it will come straight back in.
- Use good bait. A little peanut butter or chocolate hazelnut spread works better than cheese.
- Place traps against the wall. Mice prefer to run along edges. Set the trap at right angles to the wall, with the bait end facing it, wherever you’ve seen droppings.
- Use several. One trap is rarely enough; put a few in a row along their route.
- Keep pets and children away. Put the traps inside a closed cupboard, behind a kitchen plinth or in a bait station that your dog and cat can’t reach. Wear gloves to empty them.
And don’t count on the cat to sort it out: many cats catch a mouse and then let it go inside the house.
Poison and ultrasonic repellers: best avoided
Rat and mouse poison may seem convenient, but in a home with pets it’s a risk. A dog that eats the bait can become seriously ill, and a cat that catches a poisoned mouse swallows the poison too. On top of that, the mouse may die under the floor or inside a wall, and the smell lingers for days. If the infestation is large or they keep coming back, call a pest control company.
Ultrasonic repellers are popular, but there is little evidence that they keep mice away for long, and the sound can bother pets such as rabbits, guinea pigs and hamsters. Be careful, too, with peppermint oil, which is often recommended: many essential oils, peppermint included, are toxic to cats.
How to keep mice out of your home: seal it properly
- Fill holes and gaps around pipes with steel wool topped with filler, or with mortar. Expanding foam on its own won’t stop them: they gnaw straight through it.
- Fit fine metal mesh over air vents. Don’t block them completely: your home needs ventilation.
- Fit draught excluders or a brush strip under external doors. You’ll save on heating, too.
- Store food in jars or sealed containers, including pet food, birdseed and seed mixes. An open bag of kibble in the utility room is an open invitation.
- Don’t leave food out overnight. Feed your dog or cat at set times and pick the bowl up afterwards, whether they eat from an ordinary bowl or a silicone slow feeder with 5 zones.
- Keep the kitchen clean: no crumbs behind the toaster or the oven, and rubbish in a bin with a lid.
- Tidy the shed and the garden: no compost with food scraps right next to the house, and no logs or clutter propped against the outside walls.
How to clean up mouse droppings
Mice can spread germs through their droppings and urine. That’s why you shouldn’t sweep or vacuum them up dry, as you’d stir up dust. Put on gloves, dampen the area first with water and a cleaning product, wipe everything up with kitchen roll, put it in a bag, tie it tightly and throw it in the bin. Then wash your hands thoroughly.
If the mice are already inside and you want more ways to get rid of them, here’s our guide on how to get rid of mice in your home. With several well-placed traps and the gaps sealed, the problem is usually solved quickly. Do it now, at the start of autumn, and you’ll have a peaceful winter.