[slow_typist]

Just curious, you poisoned them once and no mice returned ever since? In my house I had mice during the cold/wet season. Attempts to get rid of the population by killing them were futile. (House is now free of mice though. I secured every single possibility to get in during the summer. I read some mice can get through gaps that are 1 cm or .4 inches wide.)

[flakes]

We did do a lot of work sealing the exterior of the home, as well as removal of bird feeders near the house itself. The poison likely wasn’t a silver bullet, but I recall it (along with removing any access to easy food) having the most dramatic impact overall.

[firmretention]

Yeah, without sealing entry points, they just keep coming. Not only can they can squeeze through tiny holes, they leave a trail of pheromones behind them letting other mice know where to come in. Mice infestations are awful. Hate the buggers.

[slow_typist]

Ah I did not know the pheromone part. So it could be a completely unrelated clan that moves in next time.

In older houses it is nearly impossible to find all entries… they can climb, and will even enter through the roof.

[firmretention]

Yup. My house is 50 years old and a townhome. I was killing 3-4 mice a week at one point! Got the entry points sealed and it's down to 2-3 a year. Will probably never get it down to zero because they can get in through my neighbors and find their way here somehow.

[slow_typist]

My house has a newer adjacent part with its own roof, pretty isolated from the old house. But I had mice on both attics. Finding their way from one attic to the other was the easiest part. But I needed infrared camera surveillance to figure where they entered the building. From the footage it was pretty clear that they never stayed long in the new attic. They entered through the new building, climbed up to the attic, than traversed to the old attic where they probably did all kinds of mouse things including raising their offspring.