Oh, that's very interesting. Particularly since the phrase is roughly appropriate to the situation. I wonder if that's coincidence, or if the duck has recognized the context (i.e. frustration) the phrase would be used in? I know European starlings can be taught to mimic human speech, but they mostly seem to repeat phrases more or less randomly, or when excited. Whereas parrots will actually use words in the right contexts, and even make up new words or phrases for new situations.