The first cold snap of the season usually brings two things to Calgary homes: the furnace kicking on, and mice looking for a way in. If you’ve heard scratching in the walls, found droppings in a cupboard or noticed the dog staring at the baseboards, you’re not alone. Fall is the peak season for calls to pest control Calgary mice services.
The good news is that a mouse problem is very manageable when you know what you’re dealing with. Here’s how to spot the signs, figure out how they’re getting in, clean up safely, and decide whether it’s a DIY job or time to call in help.
Why Mice Move Into Calgary Homes in the Fall
Bottom line: Mice are moving in to survive. As temperatures drop, outdoor food gets scarce and nights get cold, so mice go looking for three things: warmth, shelter and something to eat. A heated house with a pantry checks every box.
Calgary’s weather adds its own twist. Chinooks can swing temperatures dramatically in a matter of hours, and each cold snap that follows a warm spell sends another wave of rodents looking for cover. Homes that back onto green spaces, ravines, fields or new construction tend to see more activity, since that’s where mouse populations build up over the summer.
In the Calgary area, you’re most likely dealing with one of two species:
- House mice – Small, grey-brown, and very comfortable living inside walls, ceilings and cupboards year-round.
- Deer mice – Brown on top with a white belly and white feet. They’re more common in garages, sheds, cabins and acreages, and they matter for cleanup (more on that below).
Signs You Have Mice
Mice are mostly active at night, so you’ll often find the evidence before you ever see one. Common signs include:
- Droppings – Small, dark and roughly the size of a grain of rice, usually along walls, in drawers, under sinks or in pantry corners.
- Gnaw marks – On food packaging, baseboards, wiring or stored boxes.
- Sounds – Scratching or scurrying in walls, ceilings or under floors, especially in the evening.
- Nesting material – Shredded paper, insulation, fabric or cardboard tucked into quiet corners.
- A musky smell – Noticeable in enclosed spaces like cupboards or storage rooms when activity is heavier.
- Pet behaviour – Cats and dogs fixating on one spot along a wall or appliance.
How Mice Get Into Your Property
Mice can squeeze through a gap about the width of a pencil. If the head fits, the body follows. That means you’re not looking for big holes. You’re looking for small, everyday gaps, such as:
- Worn or damaged weatherstripping on garage and exterior doors
- Gaps around pipes, cables and utility lines entering the house
- Dryer vents and exhaust vents without proper covers
- Cracks in the foundation or gaps where siding meets the foundation
- Openings around windows, especially basement windows
- The attached garage, which is often the main highway into the rest of the house
Walk the outside of your home at ground level with a flashlight. Anything you could slide a pencil into is worth sealing.
Why One Mouse Usually Isn’t Just One Mouse
Seeing a single mouse is easy to dismiss, but mice reproduce quickly. They can start breeding at around six weeks old, and a female can have several litters a year. A couple of mice that get in during October can turn into a real population by spring if nothing changes.
That’s not a reason to panic. It’s a reason to act early, when the problem is small and easy to solve.
How to Clean Up Mouse Droppings Safely
This is the part most people skip, and it’s the part that matters most for your health.
Deer mice in Alberta can carry hantavirus, which spreads when dried droppings, urine or nesting material get stirred into the air and breathed in. Cases are rare, but the precautions are simple:
- Don’t sweep or vacuum droppings – That’s exactly what puts particles into the air.
- Ventilate first – Open doors and windows for at least 30 minutes before cleaning enclosed spaces like sheds or garages.
- Wear gloves (rubber or disposable).
- Soak it – Spray droppings and nesting material with a disinfectant or a bleach solution (one part bleach to nine parts water) and let it sit for several minutes.
- Wipe it up – Use paper towels, bag it, and throw it out, then disinfect the area and wash your hands thoroughly.
For heavy contamination in sheds, cabins, attics or crawl spaces, it’s worth having professional pest control Calgary mice services handle it.
What Works For DIY Mouse Control (And What Doesn’t)
If you’ve only seen minor signs, some DIY steps can make a real difference.
What works:
- Sealing entry points with steel wool, metal mesh, caulk or proper door sweeps. This is the single most important step.
- Snap traps placed along walls, where mice naturally travel, rather than in the middle of the floor.
- Removing easy food sources: Pantry goods in sealed containers, pet food put away overnight, and crumbs cleaned up.
- Decluttering storage areas in basements and garages, so there are fewer places to nest.
What usually doesn’t:
- Ultrasonic repellers – Mice tend to get used to them quickly, and they don’t address how mice are getting in.
- Peppermint oil and other scents – They may make one spot less appealing, but they won’t solve an infestation.
- Poison bait used indoors without a plan – Mice can die inside walls or ceilings, leading to odour problems, and loose bait can be a risk to pets and kids.
- Trapping without sealing – You can catch mice all winter, but if the gaps stay open, new ones keep arriving.
When to Call For Professional Pest Control Calgary Mice Services
DIY makes sense for a single sighting. It’s time to bring in help when:
- You’re still seeing signs after a couple of weeks of trapping
- Droppings are showing up in multiple rooms or on more than one floor
- You hear activity inside walls, ceilings or the attic
- You can’t find where the mice are getting in
- You’re dealing with deer mice in a garage, shed, cabin or acreage
- You run a business with food, inventory or customers on site
At Progressive Pest Management, we focus on solving the problem, not just catching the mice you can see. A typical approach includes:
- A thorough inspection to confirm the species, find activity and pinpoint entry points
- Exclusion work to seal the gaps mice are using to get in
- A targeted trapping or baiting plan placed safely and strategically for your home
- Follow-up visits to make sure the problem is actually resolved
Hearing scratching in the walls? Contact Progressive Pest Management for mouse control in Calgary.