Agrius and Oreius

Polyphonte, daughter of Hipponous, offended Aphrodite by refusing her worship and becoming a devotee of the virgin goddess Artemis. Aphrodite punished Polyphonte, causing her to couple with a bear; Artemis had the animals of the forest attack her. Polyphonte returned to her father and gave birth to twin 'savage bear-like children,' Agrius and Oreius. The twins acted with impiety and violence (they did not honour the gods and ate strangers). Zeus sent Hermes to deal with them and Hermes decided to chop off their hands and feet, but Ares—an ancestor of Polyphonte—intervened; Hermes and Ares together changed Polyphonte, her servants, and the twins into birds.

As born, the twins are described in the source as 'twin savage bear-like children,' emphasizing ferocity and a bear-associated character rather than precise morphology. After divine transformation, Agrius was turned into a vulture (described as 'birds that crave for human flesh and blood'), Oreius/Orius became an eagle owl (explicitly described as a bird that 'presages little good to anyone when it appears'), Polyphonte became a small owl, and the household female servant became a woodpecker.

According to the mythic account, the twins were of 'immense strength' and behaved as predators who 'did not honour the gods and ate whatever stranger they happened upon.' Their later avian forms carry species-associated behaviors and connotations in the tale: the vulture form is linked to an appetite for human flesh/carrion, and the eagle owl form is associated with an ill-omen when seen. Their fate and transformations are directed by divine agency (Aphrodite, Artemis, Zeus, Hermes, and Ares) rather than presented as independent magical powers exercised by the twins themselves.