Aedon

In Greek mythology, Aedon (Ἀηδών), daughter of Pandareus, was the wife of Zethus. The pair had one daughter, Itylus. Aedon accidentally killed her and was stricken with grief and guilt. In pity, the gods turned her into a nightingale, which cries with sadness every night. Alternatively, she was the queen of Thebes, who attempted to kill the son of her rival, Niobe, also her sister-in-law, and accidentally killed her own daughter instead and thus, the gods again changed her into a nightingale.

Odyssey XIX, 518.

Just as Pandareus' daughter,
the nightingale of the green woods, sings out
her lovely song when early spring arrives,
perched up in thick foliage of the forest, 
and pours forth her richly modulating voice
in wailing for her child, beloved Itylus, 
lord Zethus' son, whom with a sword one day
she'd killed unwittingly—that's how my heart
moves back and forth in its uncertainty.