Carpenter bees are a problem in the Northeast. Our house had them too. They like warm areas, and primarily bore into the soffits from the bottom edge, then turned 90 degrees and bored parallel to the soffit itself. They lay larvae in the holes. And guess who likes yummy larvae? Birds! Soon after the larvae are laid, birds come and peck on the soffit to get at the larvae, so the soffits look like they've been hit with buckshot.
We simply call an exterminator annually. A professional treatment was far more effective than my efforts to get rid of the pests. For a couple hundred bucks, they keep the carpenter bees away, and that reduces the soffit damage from all the wildlife!