There are some species of solitary bees (e.g. Carpenter bees) that excavate wood in the end grain of wood and lay their eggs with a pollen pod for the young after they hatch. Not all solitary bee species are able to excavate tunnels by chewing on wood, and instead use holes that already exist, such as crevices in decaying trees, and holes in be hotels. The young are fed in the recesses until they pupate when the ends are sealed. The adults break the seal when they emerge.
This attack can be found in the edges of roofing, rafters, fascia boards, wooden shake rooks, decks, and outdoor wooden furniture.