Found this As in many myths there are variant versions. In an early account, Sophocles wrote that Tereus was turned into a big-beaked bird whom some say is a hawk while number of retellings and other works (including Aristophanes' ancient comedy, The Birds) hold that Tereus was instead changed into a hoopoe. Early Greek sources have it that Procne was turned into a nightingale, singing a beautiful but sad song in remorse for the death of her son; Philomela turns into a swallow, which has no song. Later sources, among them Ovid, Hyginus, and Apollodorus (but especially English romantic poets like Keats) write that although she was tongueless, Philomela was turned into a nightingale, and Procne into a swallow. Of these, some omit the tongue-cutting altogether. Eustathios' version of the story has the sisters reversed, so that Philomela married Tereus, who fell in love with Procne. Wikimedia Commons has media related to: Philomela and ProcneThe names "Procne" and "Philomela" are sometimes used in literature to refer to a nightingale. A genus of swallow has the name "Progne," a form of Procne. Philomela can also be poetically abbreviated to "Philomel."