Carpenter bees make nests by tunneling into wood, vibrating their bodies as they rasp their mandibles against the wood, each nest having a single entrance which may have many adjacent tunnels. The entrance often is a perfectly circular hole on the underside of a beam or tree limb.
I took this shot of a carpenter bee in flight (not an easy task ....whew!) out on my back deck today.
"Birds do it, bees do it, even educated fleas do it. Lets do it, let's fall in love."
Nikon D90, 18-200 mm lens, ISO 500, 1/2000, f5.6, -2/3ev