Winter Pest Problems – Why Rats and Mice Move Indoors When It Gets Colder

As the weather turns colder across Berkshire, it's common to see a rise in reports of mice and rats finding their way indoors. This isn't a coincidence — dropping temperatures directly change how rodents behave, and understanding why can help you spot the warning signs early.

Why cold weather drives rodents inside

Mice and rats are warm-blooded and need a steady source of food and shelter to survive. When outdoor temperatures fall, natural food sources such as seeds, insects and fallen fruit become scarce, and the cold itself makes staying outdoors far less appealing. A house offers everything a rodent needs — warmth, nesting material, and easy access to food — so it's a natural place for them to head as autumn turns to winter.

How they get in

Mice can squeeze through gaps as small as a pencil width, while rats can exploit slightly larger openings around pipework, air bricks, damaged brickwork or gaps under doors. Older Berkshire properties with traditional brick construction and cavity walls can be particularly prone to small gaps opening up over time, especially around utility pipes and where extensions meet the original building.

Signs you may have rodents indoors

Droppings and gnaw marks

Small dark droppings near skirting boards, in cupboards or under sinks are often the first sign. Gnaw marks on food packaging, skirting or wiring are also common, as rodents need to wear down their teeth constantly.

Noises

Scratching or scurrying sounds in walls, under floors or in the loft, particularly at night when the house is quiet, are a classic winter sign.

Nesting material

Shredded paper, fabric or insulation gathered into a hidden corner of a loft, airing cupboard or shed suggests a nest is being built somewhere warm and undisturbed.

Why acting early matters

A pair of mice can multiply quickly once settled indoors, and rats can cause real damage to wiring, insulation and stored belongings. Dealing with a small issue as soon as it's noticed is far more straightforward than waiting until an infestation is well established, which is why it's worth investigating scratching noises or droppings as soon as they appear rather than hoping they resolve on their own.

Reducing the risk this winter

Check your property for obvious gaps around pipes, vents and door thresholds, and have any damaged brickwork or rendering repaired before the cold sets in. Store food, including pet food, in sealed containers, and keep garden and shed areas tidy so rodents have less cover close to the house. Bird feeders are worth keeping away from walls too, since spilled seed is a reliable food source that can draw rodents right up to your doorstep.

Mice versus rats: knowing the difference

Both are drawn indoors by the same cold-weather pressures, but they behave a little differently once inside. Mice are curious and will often nest close to a food source, sometimes in kitchen cupboards or behind appliances, and their droppings are small, around the size of a grain of rice. Rats tend to be more cautious of new objects and are more likely to stay near voids, subfloors or lofts, venturing out mainly at night, with noticeably larger, more capsule-shaped droppings. Knowing which you're dealing with helps determine the best approach, which is one reason a proper inspection is worthwhile rather than guessing.

What Berkshire's older housing stock means for winter

Many homes across Reading, Slough, Wokingham and the surrounding villages combine older brickwork with more recent extensions, and it's often the joins between the two — where new pipework or cabling has been run through an existing wall — that create the small gaps rodents exploit. A short walk around the outside of the property before the coldest months set in, checking these transition points in particular, can make a real difference to how much activity you see indoors over winter.

If you're hearing scratching in the walls or loft, or spotting droppings around your Berkshire home this winter, Pest Services Berkshire offers mice and rat removal and can help identify exactly what's going on and how best to deal with it.