Mice Infestation Signs

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Do you think you have mice in your house? Have you noticed any obvious signs around your home, such as a strong unwelcome smell or scratching sounds where there should be none? There could be many mice infestation signs making it obvious there’s a problem. Or, you might have just a few subtle signs that require a closer look. Unfortunately, mouse infestations are commonplace in Canada, but there are things you can do to get rid of them! We’ve got you covered when it comes to what you should be looking for. 

Mice Infestation Signs

Mice are attracted to food and shelter, especially in cold weather. Mice reproduce very quickly, so it’s important to notice any signs of a mouse infestation quickly to prevent the mice from spreading too far. If you see mouse droppings, damaged food containers, gnawed sheets, furniture or cables, or nesting material in unusual places, chances are you’ve already got an infestation on your hands.

What Are the Signs of a Mouse Infestation?

The first step in controlling an infestation is to figure out which pest is giving you trouble. Is it mice or rats? They each have subtle differences, such as different dropping types. Rats are larger than mice and have different colored fur. They also gnaw larger holes, and their droppings are easy to identify by their bigger size. Depending on what kind of pest you have, you can choose the appropriate type of trap and bait if you want to try to catch them yourself.

Take a good look around your house with a flashlight and check every dark area and corner where mice and rats love to hide. Can you find droppings, gnaw marks, nest material, or urine stains? Have your pets been affected? Have you heard scampering noises or detected unusually strong smells? Do you see smear marks along walls where oils from mice fur make them dirty? Worst of all, do you smell a dead mouse trapped inside your walls?

Mouse Droppings

Mice tend to make the most droppings in areas where food is stored. The droppings are small and black, about the same shape and size as a grain of rice. If you find mouse droppings near food, check for holes in food boxes or bags. Mice tend to gnaw them open, consume some food, and then leave droppings and urine there. Check your pet food containers as well – mice love kibble as much as your canine and feline companions.

Gnaw Marks

Mice will chew just about anything they can sink their teeth into. Soft materials are best for their constantly growing teeth. Furniture fabrics, food boxes, paper, wood, and even electrical wiring are fair game. Because they like chewing on wires, a mice infestation can be considered a fire hazard. Naturally, mice’s gnawing habits also make cars suitable nests: they’ll hungrily chew air filters, wires and upholstery. It’s not uncommon to see mice in unused cars.

Track Their Paths

If you’re pretty sure you have a mouse in the house, you might be asking yourself, “what now?” Even if you detect mice on your property, they may have already been there for quite some time. If you can determine how they get inside and where they nest, that information can help you get rid of them faster.

Look for small holes in walls, floors, ceilings, and attic spaces. Check behind appliances for concealed mouse holes. Damaged bricks and air vents can also allow access. Outlying buildings such as sheds, detached garages, barns, and compost bins can also be a haven for mice. You could try sprinkling some flour or sugar on a path you think mice are using and see if you can detect mouse tracks. Try to seal up openings to the outside with caulk or some other material.

Strange Smells

Mice often have a strong, musky, unpleasant odor. It’s usually from their urine (although the odor can also come from their droppings and saliva) and it can be very strong and ammonia-like, depending on how many mice you have. Sometimes the smell is masked by everyday human smells such as cooking odors, so try to “sniff around” for specific odors first thing in the morning before breakfast. If you have a black light handy, you can detect urine stains that way.

Pets Behaving Abnormally

Cats are natural anti-mouse weapons. Some dogs also take interest in rodents inside the house. If you have a cat and you see it scratching at walls or acting strangely like it’s searching for something in a remote area of your home that she was never interested in before, take note. Your kitty could be trying to tell you something.

Mouse Nests

A mouse nest is usually not as ordered and compact as a bird’s nest. Often, a mouse nest is composed of shredded paper or fabric (they probably shredded it themselves), or dried plants. These nests will usually be found in the darkest corners of your house, under or behind furniture or large appliances, or anywhere that is dark, secluded, and warm. A single female mouse can birth up to ten litters a year, so it’s best to remove their nest(s) as soon as possible.

When Are Mice the Most Active?

Mice are nocturnal and rarely show themselves in the daytime, so the best chance of detecting them is at night. During cold seasons, mice are more likely to come to homes searching for food and shelter. Mice lay low and out of sight during the day when big predators may be about, and they don’t see very well in the daytime, anyway.

Scratching Noises

Sometimes mice will make it obvious that they’ve taken up residence in your house. 

Like any unwanted guest, they can be noisy. Listen for scampering noises in overhead spaces such as attics, – especially at night. Also, sounds can penetrate walls and flooring. It’s uncommon to hear them gnawing on something, but keep a sharp ear out for them when you’re laying in bed or relaxing for the night.


Did you see or hear or smell any of the above signs in your house? If you did, don’t hesitate to contact local mice pest control experts such as Hama Pest Control. If there’s only one mouse, you could try buying a mousetrap to catch it, but often, where there’s one mouse there are many.  If that’s the case, it’s time to give the pros a call – and, maybe consider getting a cat!

Jake Garza
Jake Garza
Jake is the founder of Hama Pest Control, the preferred choice for pest removal and extermination in the Greater Toronto Area. With over thirty years of experience, Jake prides himself in bringing quality, knowledge, and care to Hama Pest Control's customers.
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