The whooperswan, like its onomatopoeic Cousins, thewhistlingandthe trumpeter, belongs to anelegant society ofsisters; the mute, Bewick's, black, and black-necked fill out the ranks.
If there is a truism we should by now have come to accept, it is to avoid single point extrapolations, look skeptically at the accepted wisdom of the day, and listen for the whistling wings of the Black Swan.