(212) 219-8218
Signs of Mice in Your House or Apartment
By:
Updated:
Finding evidence that a mouse has entered your home is the first step in getting rid of it. Left unchecked, house mice can contaminate food and cause damage to walls, electrical wiring, and personal belongings.
Common Signs of Mice
When temperatures start to cool down, mice and other pests living outside seek warmer places to nest for the winter. In urban areas like New York City, their best choice might just be your nice, heated house or apartment building.
If you suspect mouse activity in your home, here are 8 signs of mice to look out for:
1. Droppings
Mouse droppings are small (about 1/8 to 1/4 inch long) and grain-shaped. Fresh feces are often dark brown or black, but they may lighten in color over time as they dry out.
When assessing clients’ homes for mouse issues, we often find droppings near areas where food is stored or accessible. This includes underneath appliances, kitchen cabinets, pantries, and along baseboards. The amount of droppings indicates how severe the infestation is.
2. Holes
Mouse holes might appear as damaged sections of walls or paneling, a small gap or hollowed crack in the foundation, or space created by crumbling mortar.Â
Mice can fit through openings as small as a dime. Check for gaps or cracks under and behind kitchen cabinets, inside closets, around doors and floor vents, and where the floor and wall meet.
3. Rub Marks
Mice like to travel in dark, protected areas where their whiskers are touching a surface. As they move, their bodies and fur rub onto these surfaces and leave greasy smudges, which we call rub marks.
When inspecting your home, use a flashlight to look for dark smudges or discoloration along walls and sidings. Check along floors, baseboards, beams, near pipes, and other hidden areas where mice are active.
4. Gnaw Marks
Mice have a constant need to gnaw on hard surfaces to prevent their teeth from overgrowing. They frequently chew on materials like wood, plastic, drywall, cables, and electrical wiring.
Check for grooves and markings along baseboards and around cracks or holes in your walls. Individual gnaw marks are small and clean-cut, consisting of two parallel grooves that are 1–2 mm apart.
5. Nests
Mice build nests from soft household materials like fabric, shredded paper, and insulation. These are typically located in dark, undisturbed areas like cabinets, drawers, behind drywall, and underneath large appliances.
You might also discover their food caches, where mice store seeds, dry food, and pet food. These are usually located within 10 feet of the nest, and may attract other pests, like cockroaches, beetles, flies, and mites.
6. Noises
Mice have a constant need to gnaw on hard surfaces to prevent their teeth from overgrowing. This behavior can create grating sounds as they gnaw on walls, floors, or insulation.
As mice move around your home, you might also hear scratching or rustling noises. These sounds are usually heard behind walls or ceilings and are more noticeable at night when mice are active. Squeaking is another common sound associated with mice, but it’s important to note that consistent or predictable squeaks might indicate a mechanical or structural issue rather than a rodent infestation.
7. Odors
Another sign that mice have invaded your home is a pungent, musky smell. This mainly comes from their urine, which releases ammonia. Mice use these odors to mark their territory and communicate with other mice.1
The smell may be more noticeable in enclosed areas like pantries, drawers, and cabinets. It’s often stronger along baseboards and walls as rodents move along, depositing microdroplets of urine as they go.
Foul, rotting odors can also come from dead mice that have succumbed to traps, poison, or natural causes. If you notice this type of odor, it’s important to locate and carefully dispose of the deceased mouse, as this can be a health hazard.
8. Unusual Pet Behaviors
If your pet hears or smells a mouse in your home, they might show unusual interest in certain areas. They might appear extremely alert and have reactions like barking, scratching, and pawing.
Where to Look
Entry Points
Mice can squeeze through openings and cracks as small as a quarter of an inch, making it easy to enter your home unnoticed. Here are some common entry points that we recommend sealing:
- Walls – Gaps around baseboards, between cabinets, and along the siding may provide potential pathways into your home.
- Utility Lines – Mice may enter through large holes and gaps around plumbing and utility lines. These are often hidden under sink cabinets and behind large appliances.
- Doors and Windows – Look for gaps around doors and window frames, as well as holes in worn-out screens and damaged weatherstripping.
- Roofs – Mice are excellent climbers and can access homes via the roof (through gutters, vents, and chimneys).
Finding and sealing entry points can prevent more mice from entering your home and stop an infestation from getting worse.
Hiding Spots
‌Mice are poor regulators of body heat, so they like to nest in warm, undisturbed areas near sources of food and water. Common hiding places for mice include:
- Crawl Spaces and Wall Voids – These provide mice with a secure environment, along with insulation and debris that they use as nesting material.
- Behind Kitchen Appliances – Mice often hide behind large appliances such as refrigerators, stoves, and dishwashers. They also tend to build food caches within or near these areas.
- Pantry Shelves – Mice often hide here while foraging for food. This can lead to contamination of food items, as mice can carry pathogens.
- Storage Areas and Closets – Cluttered spaces such as closets, storage rooms, and basements are prime hiding spots for mice.
- Attics – The secluded environment and the availability of insulation make attics an ideal location for nesting.
Conclusion
By being aware of the common signs of mice, you can take proactive steps to address the issue. Regular inspections of your home, especially in areas where food is stored and around potential entry points, can help detect early signs of a mouse infestation. If you suspect a problem, it’s important to take action promptly to prevent the infestation from worsening.
Need help with a mice in New York City or the Tri-State area? Talk to our experts today about mouse extermination and exclusion services.
About the Author
References
- Arakawa, H., Blanchard, D. C., Arakawa, K., Dunlap, C., & Blanchard, R. J. (2008). Scent marking behavior as an odorant communication in mice. Neuroscience & Biobehavioral Reviews, 32(7), 1236–1248. https://doi.org/10.1016/j.neubiorev.2008.05.012 ↩︎