This morning the turkeys began behaving oddly. The largest bird walked a short distance away from the others and began shrieking continually and loudly. The rest of the flock then huddled together, separate from the one that was calling. The reason for this behaviour soon appeared. A large-ish hawk began swooping on the smaller birds around my bird feeders. The hawk persisted in its attempts long enough for my DH to go fetch his camera with the zoom lens and take pics. He identified the raptor as a Cooper's hawk.
Although adult turkeys were not in danger from a hawk this size, it still speaks volumes that the flock leader, on seeing a hawk, unhesitatingly put his life on the line to save the others by separating from them and calling attention to himself. That brave turkey deserves a medal!