From Wikipedia:
Apollo had a raven which was once snowy WHITE. He turned it to BLACK when he was told of his lover's adultery while carrying his son!
Mythology
See the story at
constellations Crater and
Hydra.
Once the crow had beautiful silver or snowy white feathers and could speak to humans, but that all changed. As Apollo's sacred bird, the crow (or Raven) was told to watch over his pregnant love, Coronis. Coronis slowly lost interest in Apollo and was attracted to a mere mortal. The crow, who was secretly spying on her, reported her unfaithfulness to Apollo. In a rage of anger he unfairly turned the loyal raven's feathers black and took away its ability to speak. Coronis was killed by Apollo's twin sister Artemis. The child of Coronis and Apollo was rescued and raised. He then became known as
Asclepius, the god of medicine and healing.
Lots of healing and black and white references here.
Cheers, MA