spread from plantings
not a carpenter bee, I don't think
Red leaves photo added on inat.
This species has been present in the area of Nothern Virginia for years. They may have escaped from a nearby collection originally, and turn up on the Potomac River from time-to-time, typically with Canada Geese. I have never seen younger birds, so I don't believe they are breeding in the wild.
Steeper forehead, shorter and slightly down-turned bill point toward this species vs. Canada Goose, though some characters can show overlap. I believe the (small, trailing) individual in the group in the observation linked below is the same:
Heard vocalizing with the weaker (than American) and two-parted "CA-uh".
Probably this genus
Probably this species.