I'm from northern MN and some years it seemed like the whole forest floor would move from all the mice scurrying under the leaves. I had enough problems with mice in my house that I had to string my stretched fur on wires stretched across the fur room. I had a ermine move in and he stayed until you couldn't find a mouse within 100 yards of the place. He even got to the point he would take bits of beaver meat from my hands, we nicknamed him "Herman the Ermine". Surprisingly we never had an infestation of mice in the house like that again.
