I have a book by Bernd Heinrich, Mind of the Raven (1999), subtitled "Investigations and Adventures with Wolf-birds". He did research with ravens for years. I t

I have a book by Bernd Heinrich, Mind of the Raven (1999), subtitled "Investigations and Adventures with Wolf-birds". He did research with ravens for years. I tried to find where he mentioned the behavior. One thing he noted throughout his research was that ravens generally will not so much as touch a carcass unless and until they have spotted wolves, a bear, or eagle eating it. And, they would much rather harass an eagle and get it to drop what it has stripped off than to dig in themselves.