During the spring, people often notice large, black bees hovering around the outside of their homes. These are likely to be carpenter bees, named for their habit of excavating holes in wood, in order to rear their young. Carpenter bees prefer unpainted, weathered wood, especially softer varieties such as redwood, cedar, cypress and pine. Painted or pressure-treated wood is much less susceptible to attack. Common carpenter bee nesting sites include eaves, rafters, fascia boards, siding, wooden shake roofs, decks and outdoor furniture.
Though seldom as destructive as termites, carpenter bees can cause cosmetic and structural damage. Female carpenter bees excavate new tunnels in wood for egg laying, or enlarge and reuse old ones. Significant damage can occur when the same pieces of wood are infested year after year. Holes in the wood surface also facilitate moisture intrusion, rot and decay.