I'd consider trapping or shooting one somewhere else, then hanging it from a tree. They seem to get the message.
Aluminum pie tins hung from strings tend to keep crows and other pests away from gardens, but I don't know whether it will keep them out of trees.
People are like rifles. Some are tried and true, having great eyes, personality, and fun to be with. Others never seem to hit the mark with you. Still others go off half-cocked. Still, it's nice to know most of them.