This spring when I opened up our camp, I hung out the bird feeders and other decorations and yard art brick-a-brack-a. one of the Items was a ceramic troll cave.
A week or so after we hung it out, we had a nesting pair of Black Capped Chickadee's make it their home and eggs were laid!
The Pair flew in and out for about 3 weeks with nesting stuff, Stay tuned and see what happens next . . .