One box on my route has consistently had hair in it. Once when I checked it, there was also a big old bumblebee on the top of the hair.
I asked a fellow nest box monitor about it and she said that it is not uncommon for bumblebees to do something like that in a box. I decided to leave the hair and see what happened. If it was a bumblebee nest, I thought it would be interesting to observe. Earlier this month, though, there was still lots of hair, but no evidence of bees, so I removed the hair.
Yesterday, when I returned to that box, there was more hair… And this time, I met the culprit: not a bumblebee at all.
I think I’ll name her BumbleMouse.