“Field studies have shown that ravens “call” wolves to large animals they find dead. Why invite wolves to dinner? Because, unlike birds of prey, the raven lacks a bill or talons designed to open a carcass. Someone else—wolf or human hunter or motor vehicle—needs to do the job. Magpies have been observed working with coyotes in much the same way as ravens work with wolves, and the canine hunters have learned to listen when corvids call.”