I watched two ravens pull a neat trick. A bald eagle came near their nest in a lone pine next to a bog. The male jumped off the nest and swooped in the opposite direction under the eagle. The eagle cocked his head to eye the male and flared his wings to turn to follow the male. The female did the same thing as the male, caught up to the eagle and nailed the eagle in the back of the head so hard it made his flight erratic. She cawed just before she struck the eagle. Upon her caw, the male immediately went up with great flapping of wings, inverted, looped and dove on the eagle, striking him in the back of the head. She did the same... he did the same. Six times the eagle was smacked in the head until it hit the ground.

They circled the eagle and cawed for about 30 seconds. I think they were telling the eagle to caw off. It did.

I got some stories I wouldn't tell here but ravens and moosebirds (Canada Jays) can be trained to aid a hunter.