Every September, as overnight temperatures on the prairies drop, house mice and deer mice start looking for somewhere warm with a food supply. A barn with spilled feed, a shop with a wall cavity, a grain bin, a tractor cab or a parked RV all qualify. The mice you see in October got in during September, so the best time to set up control is before the first hard frost.
This guide covers the three parts of a fall rodent plan: shutting off food and entry, choosing between traps and bait stations, and cleaning up safely afterward. Everything below about the products follows the manufacturer's label. Always read and follow the label on the package you buy.
1. Cut off food and entry first
Traps and bait work far better when mice have fewer easy meals.
- Store feed, pet food, bird seed and grass seed in lidded metal or heavy plastic bins rather than open bags.
- Sweep up spilled grain and feed daily during the fall move-in period.
- Walk the outside of each building at ground level. A mouse can pass through a gap about the width of a pencil. Stuff steel wool or copper mesh into gaps around pipes, wiring and door sills, then seal with caulk or sheet metal.
- Keep grass and weeds trimmed back from foundations and move lumber and pallet piles away from walls.
2. Traps or bait stations?
Both have a place. The decision usually comes down to whether children, pets or livestock can reach the location, and whether you need to find the carcass.
Snap traps and wood traps
Reusable and poison-free, so they are the right choice in a tack room, a house-attached garage, a vehicle or anywhere you want to see exactly what you caught. Set them with the trigger end against the wall, because mice run along edges. Use several traps a few feet apart rather than one trap in the middle of the room, and check them daily.
- Tomcat Mouse Snap Traps, 2-pack
- Tomcat Mouse Wood Traps, 4-pack
- Tomcat Rat Snap Trap for the larger footprints and droppings that mean rats rather than mice.
Live-catch and glue traps
A multiple-catch live trap holds several mice at once without bait or poison, which suits a granary or feed room where you would rather not use a rodenticide near stored feed. Glue traps are a simple monitoring tool along a known runway. Both need to be checked at least daily.
Bait stations
Tomcat Mouse Killer and Rat Killer bait stations use bromethalin, which the label describes as acting on the rodent's nervous system; mice typically eat a lethal dose in one night and die over the following days, so you will not usually see a result the next morning. The disposable stations come pre-baited and sealed and are designed for indoor use against house mice, with a child-resistant (Tier 3) design; the refillable stations take replacement bait blocks for ongoing control.
Label placement directions, in short:
- Put stations where the activity is highest: along walls, in corners and beside holes, where droppings or gnaw marks have been seen.
- Keep bait available for at least 7 days so every mouse in the building gets a feeding.
- Keep stations away from children, pets and livestock. Bait is harmful or fatal if swallowed, so a station should never sit where a dog, cat, calf or horse can reach it.
- Wear rubber gloves when picking up dead rodents and when collecting used stations, and dispose of them in the household garbage as the label directs.
- Tomcat Mouse Killer Disposable Bait Station, 28 g (single) or the 4-pack
- Tomcat Mouse Killer Refillable Bait Station with 8 refills or 16 refills
- Tomcat Rat Killer Disposable Bait Station, 113 g
- Tomcat Mouse and Rat Attractant Gel to dab on trap triggers when mice are ignoring them.
One more thing on rules: Health Canada requires that rodenticide bait placed outdoors above ground, or anywhere children, pets or livestock can reach it, sit inside a tamper-resistant bait station. The consumer Tomcat stations sold here are sealed stations for that reason. Do not break open a station to use loose bait.
3. How many, and where
A reasonable starting point for a typical farm shop or small barn is a trap or station every 2 to 3 metres along the walls where you see droppings, plus one at each doorway and near any feed storage. Mice rarely travel far from cover, so the middle of an open floor is wasted space. If a trap or station has caught nothing in a week, move it rather than waiting.
4. Clean up safely: deer mice and hantavirus
Deer mice are common across rural Alberta and can carry hantavirus, which is spread when dried droppings, urine or nesting material are stirred into the air. Alberta Health's cleanup advice for mouse-contaminated areas is simple and worth following every time:
- Open doors and windows and stay out of the space for at least 30 minutes before you start.
- Never sweep or vacuum droppings, nests or dead mice dry.
- Wear rubber gloves. Soak droppings, nests and carcasses with a solution of one part household bleach to nine parts water (or a household disinfectant) and let it sit for five minutes.
- Mop up or pick up with paper towels, bag it, seal the bag and put it in a garbage can with a tight lid.
- Wash gloves before taking them off, then wash your hands.
For a heavy infestation in a building you need to work in, Alberta's Health Link (811) can advise on extra precautions.
Fall checklist
- Lidded bins for all feed and seed.
- Walk the perimeter and seal pencil-width gaps.
- Traps along walls in living and tack areas; sealed bait stations in shops, bins and outbuildings out of reach of animals.
- Check daily, keep bait available 7 days, move what is not working.
- Gloves, bleach solution, no dry sweeping.
Everything in this guide is stocked at our store in Millet and ships across Alberta. Browse the full Tomcat range or the Pest Control category, or call (403) 679-5334 if you want a hand sizing a plan for your buildings.
Sources: Tomcat Canada product label information for Tomcat Mouse Killer Disposable Bait Station (Scotts Canada); Health Canada, Use restrictions for commercial class rodenticides in agricultural settings; Alberta.ca, Reducing the risk of hantavirus.