Mice in Alberta: House Mice vs Deer Mice, and Why It Matters for Your Family

If you have heard scratching in the wall this week or found droppings in the garage, you are not imagining the timing. The first cold nights of October are when mice in Alberta move indoors, and Edmonton homes get two different kinds. One is a nuisance. The other can carry hantavirus. Knowing which one you have changes how you clean up, how urgently you act, and what your mice control Edmonton technician will do when they arrive.

The two mice that get into Alberta homes

Edmonton is rat-free, so when something is moving in your walls it is one of two animals: the house mouse or the deer mouse. They look similar at a glance and they get in the same way, but they behave differently once inside.

House mouse (Mus musculus)

Small, uniformly grey or greyish-brown, with a nearly hairless tail about as long as its body. House mice live alongside people year-round, breed indoors, and are the mouse you find in kitchens, pantries and basements in the middle of the city. They do not carry hantavirus.

Deer mouse (Peromyscus maniculatus)

Two-toned: brown or reddish-brown on top with a white belly, white feet and a tail that is dark on top and white underneath. Bigger eyes and ears than a house mouse. Deer mice are a field and forest animal that comes indoors for the winter, which is why they turn up in garages, sheds, attics, acreage homes and any house that backs onto a ravine, park or farmland. They are the reservoir for hantavirus in Alberta.

What hantavirus actually is, without the scare

Hantavirus cardiopulmonary syndrome is a rare lung illness. People are infected by breathing in virus particles stirred up from the urine, droppings or saliva of infected rodents, almost always deer mice. It does not spread from person to person in Canada. Alberta sees only a handful of cases most years, but the illness is serious: roughly 30 to 40 percent of people who develop it do not survive, according to the University of Alberta.

The pattern behind those cases is consistent. Someone opens up a garage, shed, camper or cabin that has been closed for months, finds a mess of droppings and a nest, and sweeps or vacuums it. That is the moment the dust goes airborne. Which is why the single most useful thing in this post is the next section.

How to clean up mouse droppings safely

These are the steps Alberta Health recommends, and they apply whether you think you have deer mice or not, because you cannot always tell from the droppings alone.

• Air it out first. Open doors and windows and stay out of the space for at least 30 minutes.
• Never sweep or vacuum droppings, nests or dead mice. That is what creates the dust you do not want to breathe.
• Wear rubber gloves and a mask before you touch anything.
• Soak, do not wipe. Mix one part household bleach with nine parts water and thoroughly wet the droppings, nest material and any dead mice. Let it sit for at least five minutes.
• Pick it up with paper towel, bag it, seal the bag, and put it in the outdoor garbage.
• Disinfect the surfaces with the same bleach solution, then wash your gloves before taking them off and wash your hands.

For a heavy infestation in an attic, crawlspace or wall void, or a space where insulation is soiled, that is a job for equipment and respirators rather than a bucket and gloves. Our technicians handle the cleanup as part of the removal when it is needed.

Where deer mice get into Edmonton homes

Deer mice do not need much: a gap the width of a dime is enough. The entry points we find most often in Edmonton and the surrounding communities are the seal along the bottom of the garage door, gaps where utility lines and dryer vents pass through the wall, cracks in the foundation that open with each freeze-thaw cycle, the seam where siding meets the concrete, unscreened roof and soffit vents, and the underside of decks and sheds. Homes in St. Albert, Sherwood Park and Spruce Grove that back onto fields, ravines or trail corridors get the most deer mouse pressure, and parked RVs, trailers and vehicles are a favourite winter shelter.

Signs you have mice, and which kind

• Droppings: small, dark and rice-shaped for both species. Deer mouse droppings are slightly larger and pointed at the ends, but do not rely on that alone.
• Nests made of shredded insulation, paper or fabric, often in a garage corner, a stored box, an engine bay or the back of a drawer.
• Scratching or scurrying in walls and ceilings after dark.
• Chewed pet food bags, birdseed, or cardboard.
• A cached pile of seeds or dog kibble in a hidden spot is a deer mouse trademark. House mice nibble where they find food; deer mice hoard.

If you actually see the animal and it has a white belly and white feet, treat the cleanup as a deer mouse job.

Getting rid of mice in Alberta: what works

Traps and bait deal with the mice already inside. Sealing the entry points is what stops the next family from moving in, and it is the part most DIY efforts skip. Our approach on every mice and rodent control job is an inspection to find how they are getting in, targeted treatment with stations placed where kids and pets cannot reach them, and exclusion work on the gaps we find. Our 30-Day Rodent Control program starts at $449 plus GST, with a free quote before any work begins. If you get mice every fall, year-round Home Shield protection starts at $80 per month; our mice cost guide compares the two.