Sure, it is written...:lol: (Although it could be misspelled, of course)
It is a text in which the author (English, not American) lists a few ways of calling people related to animals and that is the reason I said there was no context:
«The animal lurking inside human beings was obvious, screeched Punch with delight: slimy reptiles, old ducks, snakes in the grass...»
Being Punch the famous English Magazine.
So, What kind of person was an «Old duck»?
Thanks!!