Eastern Carpenter Bee
Eastern carpenter bees somewhat resemble bumblebees but have a noticeably black, shiny abdomen. (Bumblebees, although about the same size and shape, have a noticeably fuzzy abdomen, usually with a prominent yellow band across it.) You can also distinguish the two by their behaviors: Carpenter bees are rather solitary and excavate their nests in wood. A small pile of sawdust beneath a hole about 3/8 inch in diameter is a clue to their presence.