They will hollow out a piece of lumber pretty thoroughly. And they keep coming back. Hornets in the back yard or somewhere out of the way is an awesome cure. They might eat a few bees too but it's nothing compared to the other options.Thanks guys. I thought carpenter bees were more like bumble bee shape, but the body discriptions I found sounded like they could be carpenter bees. There were 3 of them checking out a swarm trap.