Hi Helene, nice to see your post & hope you’re keeping your chin up in this strange time. Last year I devised swarm bait boxes out of two styro brood boxes that had been in use the previous season. I cut green foam board insulation to fit the tops and bottoms and duct-taped them on, then carved a small opening in the bottom boards. They were very light and easy to rig up into the trees!
…unfortunately no bees moved in. I’m going to try this again tho & will let you know what happens 