I can't help it.
When I see a bluebird nest box along the road, I have to stop and take a look inside. This time of year, if they're full of nesting materials, I clean them out (to make them more attractive to the birds that hang around during the winter. Bluebirds often roost in them to get out of the cold).
When I spotted this weathered box on Great River Road near the Alma cemetery, I stopped to take a peek. It was full of nesting materials. Maybe there'd be a surprise inside, something with an exoskeleton or fur.
I popped the top.
It was packed with fur, cattail "fluff," grasses and and other plant materials. Eight pairs of beady little eyes looked back at me. The creatures attached to them were frozen in panic. Four of them bounced right out of the box - making me take a step back. Three dug deeper into the soft bedding.
The last one just sat there, cringing as I watched in awe. Peromyscus - Mice! I couldn't determine which species: either white-footed or their cousins, deer mice.
Eventually, all of them took the great leap, but the last one just couldn't get his body through knot hole. After a few minutes, he backed out and bolted from the "official" entrance in the front of the nest box.
I think mice are cute. But, in a bluebird box, they're trouble.
In fact, according to bluebird conservationists, if mice are a in the boxes during the off season, bluebirds won't be safe during the nesting season. So - I put on my gloves, donned my filter mask, stood up-wind and emptied out the box. (Don't be cavalier, protect yourself when cleaning out nest boxes. Mouse nests can be dangerous to your heath).