Well...we traumatized the ducks by catching them one at a time, listening to them, and taking each one's picture so we could remember which was which, and it turns out that we have 8 ducks and 2 drakes (and we already knew that those two were drakes). Or is it possible that any of them are drakes even though they are definitely quacking? (One did switch between loud quacking and the more drake-like sound, but the others were CLEARLY quackers.). If it really is just two drakes, then we can probably keep them all together.