Mouse Nest in the House: How to Find, Check and Remove It

Image: Amelia Martin/Shutterstock

A mouse nest is a loose, untidy ball of shredded material such as paper, cardboard, fabric or loft insulation, usually with droppings and food scraps nearby. Mice hide their nests in warm, dark spots close to food: behind kitchen appliances, in the loft, under floorboards or inside wall cavities. One nest often holds one or two mothers and their babies. If you find one, check whether it’s still in use before you touch it.

What does a mouse nest look like?

A mouse nest is a loose, roughly round pile of shredded material, with a softer, finer lining inside where the babies lie. From the outside it can look like a heap of rubbish: torn paper, bits of fabric, chewed cardboard, loft insulation or dried leaves. Look closely and you’ll often see a hollow in the middle and an entrance hole in the side.

An active nest usually has fresh droppings, a few chewed food scraps and a musty smell around it. Nests built in a hurry, such as in a drawer or a box in the loft, can be just a flat pad of shredded paper.

What does a mouse nest smell like?

Musty and sharp, like stale urine with a hint of ammonia. Mice urinate often to mark their runs, so the smell builds up around a nest that’s been used for a while. A strong, sweet, rotten smell is different: that usually means a dead mouse, sometimes a baby left behind in a nest.

Is it a mouse nest or a rat nest?

Rats build bigger, messier nests and often burrow outside, under sheds, decking and compost heaps. The droppings tell you most: mouse droppings are 3 to 6 mm long, about the size of a grain of rice, while rat droppings are 12 to 18 mm.

Why do mice nest?

Mice build nests to sleep in, keep warm and raise their young. A nest is also where they carry food back to, so you may find seeds, nuts or pet food stashed close by. Indoors, house mice can breed all year round, so they nest wherever they settle.

Do male mice make nests?

Yes. All mice make somewhere to sleep, males included. The bigger, well-lined nests are usually built by females for their litters, and two females often share one nest and feed each other’s young.

When do mice nest?

All year round indoors. In buildings, house mice can breed in any month, so they build and use nests through the winter too. Outdoors, mice breed mainly in the warmer months. Autumn is when most mice move inside looking for warm places to nest, so nests often turn up from September onwards.

What are mice nests made of?

Whatever soft material mice can find and shred near the nest site:

• Paper: newspaper, tissues, kitchen roll, cardboard boxes and books.
• Fabric: old clothes, towels, wool, and the stuffing from sofas, cushions and mattresses.
• Insulation: loft insulation, pipe lagging and foam.
• Plant material: dried grass, leaves, straw and moss, mostly in sheds and gardens.
• Plastic: shredded carrier bags and packaging.
• Hair and feathers: from pet bedding, cushions and pillows.

Piles of shredded paper or fabric, or chewed loft insulation, are a strong sign a nest is close by.

Where do mice nest in a house?

Mice nest in hidden, warm spots close to food. In homes, that usually means the kitchen, the loft, inside cavity walls and the spaces between floors. These are the places to check first:

Where do mice nest in walls?

Inside cavity walls, boxed-in pipework and the voids behind kitchen units. You’ll usually hear them before you find the nest: scratching at night, often near pipes or the kitchen. Here’s how to get rid of mice in the walls without opening the wall.

Can mice nest in furniture or beds?

Yes, though it’s less common than kitchens and lofts. Mice nest inside sofas, armchairs and divan bed bases, where the stuffing gives them soft material and a dark space. Look for droppings on or under the furniture, shredded stuffing and a musty smell. Mice in a bedroom are often just passing through to look for food, so keep snacks out of the bedroom.

Where do field mice nest?

Outdoors, in shallow burrows under sheds, hedges, log piles and compost heaps, and in long grass. In autumn they come into sheds, garages and sometimes houses, and nest in boxes, sacks and stored cushions. Not sure which mouse you’ve got? See the types of mice in the UK, and how to deal with field mice in the garden.

How to find a mouse nest in your house

Work back from the signs mice leave on their way to and from the nest:

1. Follow the droppings. There are more of them, and they’re fresher, the closer you get to the nest.
2. Follow the smell. The musty, ammonia smell is strongest near the nest.
3. Use a torch behind and under appliances. Pull out the fridge, cooker and washing machine if you can, and unclip the kickboards under kitchen units.
4. Look for shredded material. Torn paper, fabric or insulation in cupboards, drawers, boxes and the loft.
5. Listen at night. Scratching or squeaking from one spot in a wall, ceiling or floor.
6. Check stored things. Boxes in the loft and garage, bags of old clothes and the airing cupboard.

If the nest is somewhere you can’t reach, don’t break into walls or floors to find it. A pest controller can trace the runs and treat the area without opening up the building.

Signs of a mice nest in the house

• Noises at night: scratching, scurrying or squeaking in walls, ceilings or under floors, often from the same spot.
• Shredded material: torn paper, chewed cardboard or loose stuffing in dark corners, cupboards or behind appliances.
• A musty, ammonia smell: strongest in enclosed spaces close to the nest.
• Droppings: dark, 3 to 6 mm, like grains of rice, with lots of fresh ones in one area.
• Gnawing: chewed packets, wood, plastic and cables.
• Smear marks: dark, greasy marks along skirting boards and around holes, from the mice’s fur.
• A food stash: seeds, nuts, pet food or cereal hidden in a corner or a box.
• Your pet’s behaviour: a cat or dog sniffing or staring at the same wall or cupboard.

For the full list and what each one means, see the signs of mice in your house.

How many mice live in a nest?

Usually one or two mothers and their babies. Female house mice often share a nest, most often in pairs, and nurse each other’s young. With 5 to 8 babies in a litter, one busy nest can hold a dozen mice or more.

A home rarely has just one nest, either. Mice in the same house usually belong to one family group, and as numbers grow, they build more nests in other warm spots close to food.

Do mice live in groups?

Yes. House mice live in family groups that share part of a house: several females, their young and usually one or more males. If you see one mouse, others are almost certainly close by.

How often do mice breed?

Very often. Indoors, a female house mouse can have a litter roughly every month, all year round, or 5 to 10 litters a year. She can be pregnant again within a day of giving birth, and her daughters start breeding within a couple of months. That’s how a couple of mice in autumn can turn into an infestation by winter.

How many babies do mice have?

Usually 5 to 8 in a litter, sometimes up to 12. Newborn mice are tiny, pink, blind and hairless.

When do baby mice leave the nest?

At about three weeks old. Baby mice stay in the nest while they feed on their mother’s milk and are fully weaned by around 23 days. After that, they start leaving the nest to find food, and soon move off to build nests of their own.

What should I do if I find baby mice?

Don’t touch them or move the nest. Baby mice can’t survive without their mother, and if they die inside a wall or under the floor, you’ll have a strong smell for weeks. The mother is usually close by and will come back, so the whole family needs dealing with at once. This is the time to call a pest controller, who can remove the nest and treat the adult mice together.

Is a mouse nest dangerous?

Mostly to your home and food. Mice chew whatever they can reach to build the nest and get to it: loft insulation, cardboard boxes, stored clothes, wood, plastic pipes and electrical cables. Chewed cable coating can be a fire risk. In garages, mice also nest in car engine bays and chew the wiring there. Here’s how to keep mice out of a car engine.

Mice also leave droppings and urine in and around the nest, and these can carry germs such as Salmonella and Listeria. The risk comes from touching the nest or breathing in dust from it, which is why you shouldn’t sweep, vacuum or handle a nest with bare hands. Here’s how to clean up mouse droppings safely.

Does a mouse nest mean an infestation?

Usually, yes. A nest means mice have settled in and are probably breeding, not just passing through, and one nest rarely means one mouse.

How to tell if a mouse nest is active

• Fresh droppings: soft, dark and shiny. Old ones are dry, grey and crumble.
• Newly shredded material or fresh chew marks nearby.
• A food stash with fresh scraps.
• A strong, musty smell.
• Noises from that spot at night.

An old, dry nest with only grey, crumbly droppings may have been abandoned. Mice often move to a new nest close by rather than leave the house, though.

What to do if you find a mouse nest

1. Leave it alone for now. Don’t poke, sweep or vacuum it.
2. Check whether it’s active using the signs above.
3. If you see or hear baby mice, call a pest controller rather than moving the nest.
4. Remove an empty nest safely using the steps below.
5. Deal with the mice too. Removing a nest doesn’t make mice leave: they’ll simply build another. Follow our guide on how to get rid of mice.

How to get rid of a mouse nest safely

1. If the nest is in a closed space, open windows or doors and let it air for 30 minutes.
2. Put on rubber gloves. A dust mask helps if the nest is dry and dusty.
3. Spray the nest and any droppings with disinfectant until wet and leave it for 5 minutes. Don’t sweep or vacuum it dry.
4. Lift the nest with paper towels, put it in a bin bag and tie it. Put that bag inside a second one and put it in your outside bin.
5. Disinfect the area, and wash any fabrics from in or near the nest on the hottest setting the fabric can take.
6. Throw away any food the mice may have touched, then take off your gloves and wash your hands.
7. Find out how the mice reached the spot and block the gap. Here’s how to find where mice are getting in.

If the nest is inside a wall, under the floor or full of baby mice, leave it to a professional.

How to stop mice nesting in your house

• Cut off food. A mouse needs only about 3 g of food a day, so store food in sealed tins and tubs and clear up crumbs before bed.
• Clear nesting material. Get rid of piles of cardboard boxes, newspapers and old clothes in the loft, garage and under the stairs, and store what you keep in plastic boxes with lids.
• Keep pet food and bird seed sealed in metal or hard plastic bins.
• Check the garage and car. Keep the garage tidy and look in the engine bay if the car isn’t used often.
• Block the way in. Seal gaps around pipes, cables and vents, and fit brush strips to gaps under doors.