Why Mice Move Indoors in the Fall

Mice move indoors in the fall because they are looking for warmth, shelter and food as temperatures drop. Homes and apartment buildings offer all three, and mice can squeeze through very small gaps to get in. In New York City and on Long Island, late fall is when many homeowners first notice droppings or hear scratching in the walls.

Here is why it happens, what to look for and what you can do about it.

Why do mice come inside when it gets cold?

Mice do not hibernate. As outdoor temperatures fall and food sources outside get harder to find, they search for a protected place to nest. A warm basement, a wall void near a heater or a kitchen with crumbs under the stove is an easy choice.

Pest activity changes with the seasons. Insects tend to be more active in the warmer months, while rodents and other pests seek shelter as the weather cools. That shift is one reason fall is a busy time for rodent calls.

How do mice get into a house or apartment?

Mice are small and flexible, and they can fit through openings much smaller than most people expect. Common entry points include:

• Gaps around pipes and utility lines where they enter the building.
• Spaces under doors, especially garage and basement doors.
• Cracks in the foundation or around windows.
• Openings around vents, dryer exhausts and air conditioners.
• Gaps where siding meets the foundation.

In apartment buildings, mice can also travel between units through shared walls, pipe chases and utility spaces.

What are the signs you have mice?

You may not see a mouse right away. More often, you see what they leave behind:

• Droppings in drawers, cabinets, along baseboards or under sinks.
• Gnaw marks on food packages, wires or wood.
• Scratching or scurrying sounds in walls or ceilings, especially at night.
• Nesting material like shredded paper, fabric or insulation.
• Grease marks along walls where mice travel the same route.

If you see these signs repeatedly in the same areas, it is worth having the property inspected.

How can you help keep mice out?

Prevention comes down to cutting off food, water and entry points:

• Seal gaps. Close openings around pipes, vents and doors. Mice can chew through soft materials, so durable sealing materials work best.
• Store food in sealed containers. This includes pet food and birdseed.
• Clean up crumbs and spills, especially under appliances.
• Fix leaks. Dripping pipes give rodents a water source.
• Reduce clutter in basements, garages and storage areas where mice can hide.
• Keep firewood and debris away from the house.

When should you call a professional?

If you are seeing signs in more than one room, finding fresh droppings after cleaning up, or hearing activity in the walls, a do-it-yourself approach may not reach the source. Rodent problems usually need both active treatment and attention to how they are getting in.

Our rodent control service starts by assessing the activity, then building a focused treatment plan. We also help you understand prevention measures for the future. After each visit, we let you know what we found, what was treated and any recommendations for your property.

Frequently asked questions

Can mice get into a house through a small gap?

Yes. Mice can fit through very small openings, so even narrow gaps around pipes and doors are worth sealing.

Are mice a problem in apartments as well as houses?

Yes. Mice can move between units through shared walls and utility spaces, so building-wide prevention helps.

What should I do if I find droppings?

Note where you found them and avoid touching them with bare hands. Repeated droppings are a good reason to schedule an inspection.

Do you offer rodent prevention as part of a plan?

Yes. Our Eastern Shield 365 Plus plan includes indoor and outdoor rodent prevention, mouse monitoring and a rodent entry-point inspection.

Get help with mice

Tell us what you are seeing and we will help you find the right next step. Request a free quote or call (516) 924-4528.