Bald Eagle Death Spiral
As they mature at the age of 5, Bald Eagles use the Death Spiral to determine the fitness of a potential mate.
The sky challenge is there to prove to each eagle that the other one is just as arrogant, assured, and fit as the other.
The eagles clasp each other’s talons and dare the other one to let go first.
The difference in the size of the smaller male to the larger female causes the birds to spiral around their axis.
Sometimes, the drive to win is so strong that the hold is not broken and the birds crash into the ground or the water.
Immature eagles practice this maneuver all the time.  In this case it is a pair of four-year-old bald eagles.
Death can occur.  These two immature eagles broke the clasp just as they got to the tree line.

Jordan Lake Neighborhood
 
Great blue herons often argue and chase one another.
Each is certain that the other heron has the better fishing spot on the bank.
This fracas started on the shore of the Haw River, inside the riprap.
The dam was stunning fish as they passed through the gates and the pickings were easy.
Unless, of course, your neighbor heron was further upstream than you were and the fish passed them first.
Both herons missed the fish and a third heron a little further downstream had it for breakfast.