Mice nesting and probably wintering in one box

 We had two boxes with mouse nests over the summer. One is empty, with maybe the start of a nest, but no mice:

The other one is getting to be in rather tall plants and has had the mouse since spring. I believe she may have had three litters there. She even carried the pups up the pole back to the box, when a couple of them jumped out. They were full grown in summer. Now she had another litter who are also almost grown:

I gave up on that. She can have the box forever. There are 31 other boxes for birds.