I took a peak at colonies in one of my yards yesterday and when I lifted the top cover off three mice took off. They had not made it into the hive but Im sure they had a nice warm cozy place between the felt wrapped over the top of colony and the telescoping cover.
This summer just about every time I would come to this yard and opene my battery case to unhook my battery there would be a mouse in it. They would make a nest on top of battery and run down the side of the battery when I opened it. I would lift battery quick and drop it on the mouse. I probably killed seven or eight like that over the summer. I took battery and left cover off of the battery case so they would not nest in it over winter. With corn or soybean and woods and swamp all around there is apparently everything needed to support a very large field mouse population there. I will have to make some kind of drowning trap for them. I am worried about attracting other pest though with the smell of dead mice. I do have lots of garden smakes that like to hang around hives in the summer. I welcome them.