Swan

In Greek mythology, the swan was a bird consecrated to Apollo, and it was therefore considered a symbol of harmony and beauty and its limited capabilities as a singer were sublimated to those of songbirds.

The swan also plays a part in the story of  Leda and the Swan in which the god Zeus (Jupiter in Roman mythology), ieduces (or in some versions, rapes) Leda in the guise of a swan. According to later Greek mythology, Leda bore Helen and Polydeuces, children of Zeus, while at the same time bearing Castor and Clytemnestra, children of her husband Tyndareus, the King of Sparta. In the W. B. Yeats version, it is subtly suggested that Clytemnestra, although being the daughter of Tyndareus, has somehow been traumatized by what the swan has done to her mother (see below). According to many versions of the story, Zeus took the form of a swan and seduced Leda on the same night she slept with her husband King Tyndareus. In some versions, she laid two eggs from which the children hatched. In other versions, Helen is a daughter of Nemesis, the goddess who personified the disaster that awaited those suffering from the pride of Hubris. Reference: Wikipedia

The swan is also associated with Etruscan mythology, in particular with the Etruscan goddess of Love, Turan. Turan was commonly associated with birds such as the dove, goose and above all the swan.