Keeping mice out of a home is mostly a matter of closing the openings they can use and removing the food and shelter that draw them in. Seal gaps around pipes and cables, fit door sweeps, store food in sealed containers and keep wood off the floor. This guide makes no claim about a North Dakota mouse season.
Key takeaways
- Mice can pass through gaps much smaller than most people expect, so check every penetration and seam.
- Seal openings with materials that a mouse cannot chew through, such as metal mesh packed under a sealant.
- Store dry food in containers with tight lids, and keep pet food sealed in a bin.
- Keep firewood and stored wood off the floor and away from the walls.
- This guide claims no North Dakota season for mice, because no current local source was found for one.
Why is exclusion more reliable than trapping alone?
Trapping removes the animals already inside, while exclusion closes the routes that let new animals arrive. Without exclusion, a trapping success can be followed by new animals using the same gap. The two work best when they are planned together.
A trap placed in the right spot will catch an animal that is using a particular route, and that is useful. It does not close the route. If the gap is still open, another animal can use it, and the cycle starts again. Exclusion is the step that stops the cycle.
The aim of this guide is the general method. A technician can map the openings in a particular building and place the trapping and sealing where they will do the most good, which is more reliable than a list of generic steps.
Where do mice usually find a way in?
Mice can use gaps around pipes and cables, gaps under doors, cracks in the foundation, vents with damaged covers and the join between the garage and the house. The most useful check is the set of penetrations where a pipe or cable enters the building.
A pipe that enters the wall through a hole larger than the pipe leaves a route that is easy to miss. A cable run through a wall without a collar does the same. Check each one from the outside and the inside, and note the ones that do not seal tightly.
Doors are the second area. A door sweep that has worn flat, a threshold that has lifted and a garage door seal that no longer touches the floor all give a route in. These are often the largest openings on the property, and they are simple repairs.
What sealing materials work best?
Mice can chew through soft materials, so a gap is usually packed with metal mesh or steel wool first and then covered with a sealant or a finishing material. Plain foam or caulk alone is often not enough for a gap that a mouse can reach.
Metal mesh and steel wool are the usual fillers, because they resist chewing. The filler is pushed firmly into the gap and then covered so that the surface is smooth and the filler stays in place. The repair should be checked after the winter, since the building moves.
Vent covers need a fine metal mesh rather than a solid seal, because air still needs to move through a vent. The mesh keeps out animals while allowing the building to breathe. Check the mesh for holes at the same time as the other openings.
How should food be stored to discourage mice?
Keep dry food in containers with tight lids, made of glass, metal or hard plastic. Paper and cardboard packages can be chewed open. Keep pet food in a sealed bin, and clean up spilled grain or crumbs promptly.
A cardboard box of cereal on a pantry shelf is an easy meal for a mouse. Moving the contents into a sealed container removes that meal, and it also keeps the food fresh. Label each container with the date you bought the food so that the oldest is used first.
Pet food is a common target in a home. A sealed bin with a lid that fits tightly is the usual advice, and the bin should be kept in a place where the animal cannot push it open. Check the bin for gnaw marks each time you refill it.
What about firewood, feed and stored boxes?
Stored wood, feed and cardboard give mice shelter and nesting material. Keep them off the floor, away from the walls and at a distance from the house where possible. Clear the clutter in the garage and basement, which gives mice cover and makes droppings harder to see.
Stacks of firewood or lumber against an exterior wall make a sheltered route to the building. Move the stack away from the wall and raise it off the ground on pallets or a rack. Check the stack for signs before bringing wood indoors.
A basement or garage with many boxes is hard to inspect and easy to nest in. Keep boxes on shelves, and keep the floor clear so that droppings and gnaw marks are easy to see. A tidy space is also easier to seal.
Is there a particular time of year for mice?
This guide does not claim one. No current North Dakota source on mouse seasons was located, and the older extension circulars that came up in research are not treated as current advice. Exclusion and storage are sound practice at any time of year.
A reader may hope for a seasonal rule, such as a date on which to start sealing. The honest answer is that no current local source was found for one. The sensible approach is to check and seal the openings on a regular basis, and to respond when signs appear rather than waiting for a date.
The best guide to timing is your own building. Droppings, gnaw marks and noises in the walls are signs that the building needs attention, whatever the season.
When should I call a technician?
Call a technician if you have seen signs in more than one room, if the activity continues after your own sealing and storage changes, or if you find an opening you cannot seal yourself. A technician can map the building, place trapping where the evidence points and recommend the repairs.
A technician's inspection is most useful when the openings are hard to find or the signs are in a basement, crawl space or wall void. The report lists each opening and each repair, so you can do the simple ones yourself and get a quote for the rest.
Ask for an inspection that covers the outside of the building as well as the inside. Many entry points are visible only from outside, and a visit that skips the foundation and the garage will miss some of them.
How do I check a building for mouse entry in one afternoon?
Walk the outside first, then the basement, then the garage and the storage areas, looking for gaps at every penetration and seam. Use a torch and a notebook, and mark each opening you find. The walk gives you a list the technician or a tradesperson can work from.
Start at the foundation and walk the whole perimeter. Look where pipes, cables, vents and the gas or water lines enter the building, and where the siding meets the concrete. Note each gap you can see light through or push a finger into, since a mouse can use a gap that looks too small.
Inside, the basement and the utility room come next. Check the rim joist where it is accessible, the door sweeps, the threshold at the garage and any hatch to the crawl space. A list of gaps with a rough size and location is the most useful thing to take to the next step.
What about pets and children near traps and bait?
Traps and bait should be placed where children and pets cannot reach them. Ask the technician to show you the placement and tell you how to check the traps. Keep the bait in its label packaging, and never leave loose product where it could be eaten.
A trap placed behind a cupboard or along a wall is out of reach for most pets and young children, but the placement should be checked with the household in mind. A pet that is curious about a trap may need the trap moved, and the technician will explain where it is safe to put one.
Store any product in a locked cupboard, out of reach. If a child or a pet swallows a product, call the poison control line or 911 at once and keep the label to hand.
Frequently asked questions
How small a gap does a mouse need?
A mouse can pass through a gap much smaller than most people expect. Check every penetration and seam rather than only the obvious holes, and seal the small openings as carefully as the large ones.
Is caulk enough to keep mice out?
Often not. Mice can chew through soft materials, so caulk or foam is usually packed over a mesh or steel wool filler, and the combination is then covered for a clean finish.
Should I use poison or traps?
The choice depends on the building and the evidence. Traps are often used indoors, and any bait should be placed by its label, out of reach of children and pets. A technician can explain the options for your building.
Does a North Dakota mouse season change the advice?
This guide does not claim one, because no current local source was found. Sealing and storage are sound at any time of year, and the timing of any work should follow what you see in your building.
How do I clean up droppings safely?
Wear gloves, ventilate the room and wet the droppings with a disinfectant before wiping them up. Do not sweep or vacuum them dry, since that can raise dust. Bag the material and seal it before disposal.
Is a mouse in the house a sign of a dirty home?
Not necessarily. Mice are drawn by food, water and shelter, and they can use any gap. The inspection looks at the openings and the storage, not at the cleanliness of the house.
Should I seal everything at once?
Seal the openings you can reach safely in a first pass, and check the rest after a few weeks. Sealing in stages lets you see whether activity continues, and it avoids disturbing stored material or nests more than once.
This guide is general information for Burleigh County homeowners, not a substitute for an on-site inspection. Prices are estimates. See our disclaimer.