Common Signs of a Mice Infestation During Winter

 

Mice often try to enter homes and buildings when it gets cold outside, searching for warmth, food, and shelter. The most obvious sign of a winter mice infestation is actually seeing a live or dead mouse indoors, but there are many other clues to watch out for—even if you never see a mouse in person.

 

Mouse Droppings

 

One of the earliest and clearest signs of a mice problem is finding droppings. Mouse droppings are small, dark brown or black, and shaped like tiny grains of rice. They usually gather in places where mice explore the most, like behind kitchen appliances, inside drawers and cabinets, along baseboards, under sinks, and in pantries.

 

Chewing and Gnawing Damage

 

Mice need to gnaw on things constantly to keep their teeth from growing too long. In your home, look for:

• Gnaw marks on food packaging, boxes, or stored bags of grains, nuts, or pet food
• Shredded paper, insulation, or fabric (which mice use for nesting)
• Chewed holes in walls or floors, especially near corners or at the back of closets and cupboards
• Damage to electrical wires (which can be a fire hazard)

 

Unusual Noises

 

At night, when the house is quieter, you might hear scratching, scurrying, or rustling sounds coming from inside walls, above ceilings, or under floors. These noises are often caused by mice as they move around, chew, or build nests.

 

Unpleasant or Musky Odor

 

Many people notice a strange, lingering smell where mice have been active. As their activity and droppings accumulate, this odor becomes stronger and more noticeable. It’s usually most obvious in enclosed spaces like cupboards, closets, or basements.

 

Tracks and Grease Marks

 

Mice are creatures of habit and often travel the same paths along walls and baseboards. Over time, their bodies can leave behind faint greasy smudge marks or footprints. You might notice these along well-used mouse routes, especially in dusty or little-used areas.

 

Signs of Nesting

 

Mice build small nests from soft, shredded materials. Check for areas with:

• Torn paper, fabric, insulation, or string bunched up in hidden spots
• Nests commonly hidden in wall voids, behind appliances, inside drawers, attic corners, or under furniture
• Bits of collected food nearby as mice often stockpile small stashes

 

Pet Behavior Changes

 

If you have cats or dogs, you might notice them acting strangely:

• Staring, sniffing, or pawing at walls, cabinets, or other areas they didn't care about before
• Becoming fixated on certain corners, suggesting they smell or hear something unusual

 

Seeing Live or Dead Mice

 

Spotting a live mouse racing across the floor, or finding a dead one, is a definite sign of an infestation. Usually, if you see one mouse, there are likely others hiding nearby, as mice are social and breed quickly.

 

Why are Mice More Common in Winter?

 

In winter, mice are driven indoors by cold temperatures and food shortages outdoors. Small gaps as tiny as a dime around pipes, doors, or windows are enough for a mouse to squeeze through. Once inside, they can cause significant damage, spread diseases, and contaminate food.

 

What to Do if You Suspect an Infestation

 

If you notice any of these signs:

• Act quickly—mice reproduce fast, and a small problem can turn big within weeks
• Seal up cracks, holes, or gaps in your home's foundation, doors, and windows to stop more mice from getting in
• Store food in sealed containers
• Remove clutter and clean up crumbs and spills promptly
• Set traps in areas where you see signs of activity, or consider contacting a pest control professional for a thorough inspection and removal

By knowing these signs and what to look for, you can catch a potential mice infestation early—before it gets out of hand and causes serious problems for your home and health.