I'm 90% sure this hasn't been posted before.Maybe someone already wrote the following finding, but here it goes anyway.
Crows have been known to land on the backs of eagles for the purpose of biting their necks. The eagles never took any defensive action or showed any lack of composure. They just keep flying and ascending. As they arise in altitude, the air becomes thinner, which causes the crows a breathing interruption and would fall off the back of the eagle. The crow would regain self-control and fly away.