It’s December and the mice are moving in. Over the past few days I’ve worked on 3 new mouse jobs, 4 if you count my own house. A mouse can get through any opening large enough for their head. I’ve heard an opening the diameter of a pencil is all it takes.
Check doors, utility openings, look for small holes dug next to a concrete slab, or under a dog house. Check open expansion joints. Open up cabinets and check for droppings. If you have a storage room loaded with lots of stuff, now is a good time to move everything around and re-organize it, clean up, and keep an eye out for droppings or chewed boxes and wood.
Make sure outside doors seal tightly. Don’t leave pet food sitting around. Use something like steel wool to plug openings. Set traps perpendicular to walls, plunger in. Try a variety of baits like peanut butter or a piece of a sweet prune.
Whatever you do, get on top of it quick. Mice can reproduce at 30 days, having 6 to 8 young on average, as many as 10 times a year. It gets exponential pretty quick.