We had a crabapple tree, on campus, that had the first crotch rotted and hollowed out. Every night there would be over a half dozen tree frogs, sometimes over a dozen, that would emerge from that hollow and crawl around on the oversize windows of the dayroom, eating whatever they could catch.. After a little singing in the tree. Changed my perspective on tree hollows, to say the least.
There were a few people in there who would kill other animals, for whatever reason, but no one messed with those frogs.