I don't know why it couldn't be a Red-headed Woodpecker. While certainly
not plentiful up here, they are reported every few years over on the NY
side of The Champlain Valley. However, could it have been an Evening or
Rose-breasted Grosbeak?? While certainly smaller than your estimate, they
could appear larger with only water in the background for reference.
Dana C. Rohleder
Port Kent, NY