This is our second year with Mason bees. We are in west Michigan. First year a success and they are already filling up the house again. I followed a youtube and sewed a see through cloth bag. Chiffon or something like it. Stored the house in the barn. They said use the bag so mites don’t get in and eat the larva. I took it out of the barn this spring. The bag was full of bees and I thought they were dead. But no once I got it outside in the sun I could see they were crawling around. Over 50 bees from just a small house. I hung the bag on a fence post inside out and they eventually all flew away.
I have watched YouTubes about mason bees for years. The reason they are better pollinators than honey bees is they do a “plop belly flop” landing on the flower center, covering their whole belly with pollen.
Regarding Mason Bees :
Yes, they will fly away, but providing a good habitat
they will return and lay other eggs in the remaining areas of the nesting box.
They are feral and clumsy which is why they should increase fruit and vegetable production,
since they are solitary and according to most sources, you should see an increase in veggie and fruit production.
They are not honey producers, but are supposed to be 30% -to- 60% more effective as pollinators.
Many, or most of the bees, will return to your constructed sheltered habitat; you may wish to expand to add to provide for more bees .
Good on ya !