Fables are characterized by having a moral to the story. In this one, Aesop says that instead of envying the gifts of others we should make the most of our own.

 The peacock was proud of his beauty but wanted a sweet voice like that of the nightingale.  He pleaded with the goddess, Juno, to change his ugly voice.

Juno would have none of it and said that if she granted his wish the peacock would find something else to complain about.