My sister, Debbie, and I were sitting in the lawn near the ducks and Debbie kept commenting on how red the inside of one of the duck's mouth was. Later she saw something hanging out of the mouth, a hook with a swivel on it. That explained why he kept shaking his head. Ducks like shiny things and I've found a few things they've brought back to their pen, a parrot toy, a yellow plastic lighter, stuff like that. I guess it found the hook and swivel attractive too.
We got the ducks in their fence and cornered it till we caught the pitiful guy with the pierced tongue.
His new name? Captain Hook, or Hook, for short. We've also considered the name Pearce (or Pierce).