Garden Help Desk: Tips for keeping mice out of the house
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- House mouse
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- Adult deer mouse
We were cleaning our rental house and came across quite a few mouse droppings in some drawers. We think the mouse must have come in through an open door while our renters were moving out their furniture. Without thinking, we vacuumed them up with our shopvac and then continued to vacuum other areas of the house. We found new mouse droppings the next day. Now we’re worried we’ve exposed ourselves to hantavirus with the vacuuming (I didn’t wear a mask). I trapped the mouse today and took a picture of it. I know that deer mice are the primary carriers. Can you tell me if this is a deer mouse?
This looks like a common house mouse. It isn’t a deer mouse. Deer mice have white underbellies, legs and feet. They are generally light to medium brown in color rather than gray, which is typical of house mice. Deer mice also have larger ears than house mice.
Even though your mouse was a house mouse, you’ll still want to do a thorough cleanup of the areas where you found the droppings. This will eliminate odor problems that are common with mouse activity. Wear gloves while you do this cleaning.
Don’t assume that the mouse came in through an open door. Mice are experts at fitting through very small spaces. Even gaps as small as one quarter of an inch can give mice an entry point. Try to think like a mouse and check the door sweeps and thresholds of your rental’s exterior doors. Fix anything a mouse could fit through. If your rental has a garage, don’t forget to examine the door that leads from your garage into your home.
Go outside and check around the foundation of your rental home and fix any loose or damaged foundation vent covers, loose dryer vent covers and any other gaps along the foundation. Expanding foam caulk or steel wool can fill the gaps around the gas service line and A/C refrigerant lines to keep out spiders and insects, but for determined mice, you may need sturdier materials like hardware cloth, mortar or sheet metal. If your rental has a basement, check those windows for access points, too.
There are several kinds of traps that you or your renters can use if there are new mouse problems: adhesive traps, live traps, old-fashioned snap traps and battery-operated traps. The most important part about using mouse traps is to bait and place them properly.
First, bait the traps and place them without setting them so that the mice can get used to the traps. Use a tiny amount of nut butter (not cheese) as bait. The traps should be placed against walls, and for snap traps, the bait should be toward the wall, not away from it. Use two or more traps in each area where you’ve seen evidence of mouse activity.
Once you see evidence that the bait has been eaten in some traps, rebait the traps and set them. Check the traps frequently. Wear gloves whenever you need to handle the traps to dispose of mice.
