Even if you eliminate all the mice inside, new ones can still come in from outdoors by following scent trails.
Most likely: the entry points are still open and the scent trails are still there.
It can be really frustrating to find yourself in this situation. Because even if you trapped or eliminated every mouse inside, new ones often follow pheromone trails left by previous mice. And they find the same gaps around pipes, foundation cracks, and utility openings that let the last ones in.
Mice communicate through scent. When they travel through your Concord home, they leave urine trials that act like trail markers for the next group. It’s like putting up signs that say “safe place, food available” to every mouse in the area.
You can try to clean these trials up, but standard cleaning supplies won’t do the trick. The scent seeps into porous materials like drywall and insulation. Until the trails are eliminated with enzyme-based cleaners and the entry points are sealed, enough of the scent will still remain for you to have a problem.
At this point, you might shift your focus to sealing up gaps, but DIY materials often don’t hold. Expanding foam and caulk, to the dedicated mouse, can be chewed through and even steel wool will break down over time when it’s not backed by something more solid. So even if you seal a gap, it could be open again in a couple of weeks. Professional rodent exclusion uses chew-proof materials like galvanized hardware cloth, copper mesh, and metal flashing so mice can’t work through them.
And the whole time you’re setting traps and patching holes, mice are reproducing. A female can have up to 10 litters per year, and up to 8 pups per litter, with a gestation time of just 21 days. Even without breaking out the calculator, it’s clear that catching one or two mice per week while pregnant mice are hiding in the walls won’t quite do the job.
Breaking the cycle can’t rely on catching mice alone. That’s why professionals focus on finding every entry point, sealing them properly, cleaning scent trails completely, and treating inside and outside. Mosquito Squad of Southern NH does all of this through its rodent control services.
