Buzzing

The rhododendron was alive with bees in the sunshine this morning. I'm not sure what type of bees they are, they are quite a bit darker than the usual honey bee.
I have had a bug house for two or three years, and this winter several of the tubes were sealed. I had no idea who was inside! Then last weekend I discovered that some tubes had been pulled out and were lying on the ground, empty. There has been a magpie around a lot, and I guess he is the culprit. So sad. However, when I went out to blip the bug house for my extra, I see that several tubes are occupied again! I hope the magpie doesn't come back.