DUCK HEAD-TURNING DISPLAY. Some male ducks touch part of a wing with bill some touch speculum ( = display flag). Others nervously preen wing feathers ( = derived from displacement activity). Thus it seems that random displacement activity has become incorporated into a stereotyped part of the courtship ritual. Mallards raise wing, thus revealing speculum and attracts attention to it by preening. The Mandarin Duck, in the same display, merely touches one large feather; never preens, but it seems apparent that the Mandarin display is evolved from preening behavior.