I think this is my 4th year with Mason bees?? I can't recall exactly. Every year I add another tube holder and they do their best to fill them all.
I don't take them out of their tubes for the winter so whatever nature does I let happen. That being said, there are a gazillion of them flying around the back porch as today is the second day above the mid 60's here in Michigan.
1) I removed all the old tubes from their houses a week or so ago in anticipaion of the hatching. I put them in a different box down on the deck, away from the hives on the wall. In the past I've had issues with the hatchlings turning right around and using the old tubes instead of going up to the new ones. Moving it down and away seems to have helped that.
2) there was some kind of bee 'orgy' going on when I went out there today. They were swarming around the box on the deck and were sometimes three bees on top of each other. As one would emerge from the old tubes others would climb on and do whatever they were doing.
3) I heard chewing sounds so I thought what the heck and opened all the tubes and reeds, freeing many bees in the process that would have otherwise had quite a time chewing out. Often they were still in the cocoon but chewing out. I put them on the deck and others would come help them out. Very cool to see.
4) many of my paper tubes had the tiny holes in each cell and inside were small flying ants or wasps. NONE of the reeds had that problem.
5) some tubes had maggots or some other white grub in them. Those were given to the chickens to play with.
6) a lot of the tubes were empty and the mud had been chewed away so I'm assuming those are the ones I saw flying arouund already.
7) a few had black 'mold' in them.
other than that...they all seem to be happy.
I was swarmed a few times while opening the tubes but they don't sting so no biggie. It feels strange to see them on my arms, crawling around.