Once ravens were white, and had the most beautiful singing voices in all the land. Then the gods took fire back from the world. Vulture first volunteered to retrieve it. He flew to the sun, pushing so hard against it that all the feathers were singed from his head, bearing the scars to this day. Next, raven offered to help. He took a tree branch and flew to the sun, and catching the branch aflame, winged madly back to earth. The smoke from the flames blew back and singed his beautiful white feathers to black; the smoke so damaged his throat that he never sang again.

That was raven's sacrifice.