Every year we get lots of calls about carpenter bees drilling into logs, fascia boards, eaves, decks and other unpainted wood surfaces. Carpenter bees are big black solitary bees that look similar to bumble bees but have bare, shiny backs whereas a bumble bee's back is hairy. Unlike honey bees that reproduce in hives, carpenter bees drill into wood in order to lay their eggs. Their holes are perfectly round and about 1/4 inch in diameter.
