Carpenter bees are large black and yellow insects about one inch long that closely resemble bumblebees. The thorax is covered with yellowish hairs and the abdomen is a shiny black without hairs. The males are territorial and in the spring they often guard the potential nest sites. They discourage intruders by hovering or darting at any moving thing that ventures into the nesting area. This can create a 'human annoyance' factor and it is one that often startles and concerns the homeowner.
Carpenter bees nest in dry wood and occasionally hollow stems.
They overwinter as juvenile adults in the tunnels from the previous year. They often refurbish old tunnels in preference to boring new ones. The tunnel may be a foot or more in length. The eggs are placed in cells in a tunnel constructed by the bee. The larvae hatch and feed on the pollen and nectar and then pass through the pupal stage.