Corvus, the Crow, is a sacred bird of Phoebus Apollo in connection with giving prophetic functions. His wings were originally silver but were turned to black when he delivered bad news concerning the unfaithfulness of Cornis to Apollo.
Another story is that the bird was sent for a cup of water and returned to Apollo late, a water-snake in its grasp and a lie in its mouth. As punishment, Apollo banished the bird to the stars just out of reach of a cup of water, Crater, which is guarded by Hydra.