I have either carpenter bees or bumble bees flying around my wooden deck on the back of my house at the back door. The deck ins 12'x 20' and sits about 1 to 2 ft off the ground. I think that the bees are coming from under the deck wood. The deck is made out of 2x4 wood boards nailed to the floor joists. I'm wondering if they are tunneling into the bottom of the deck boards where it's protected from the elements. I see them landing on the deck and then crawling though the openings between the boards and disappearing under the deck boards. I sit out on the deck and they don't bother me and I don't bother them as long as they don't get too close to me.