I noticed just yesterday the presence of ‘plugs’ in the bee house. They’re most apparent in the smaller holes, but I think even the a few of the big holes have them. And now to do … nothing! The house will over-winter in the shed, or maybe I’ll just block the front.
Quite a few people place parchment paper in the holes and then remove and cut them opened to inspect for mites that eat pollen along with discarding unhealthy cocoons. They also sometimes place them in separate containers for hatching and whatnot … admittedly I skimmed or didn’t read all that information. That stuff applies to people who want the highest possible yields for farm pollination and such. Since these insects already existed in this environment, I figure they can over-winter well enough and hatch themselves in the spring without my superintendence.