The Daredevil likes to chase after me. He most certainly is a Daredevil,which is why I gave him that name!
The average eagle has 7000 feathers but only 12 are large and white. The tail feathers are very important to them! Tail feathers act like a rudder on a boat.They use them to steer with. You can see in the first shot the tail feathers tilted. He was making adjustments while chasing me. When he wants to slow down he will flair them.This captures more air and thus slows him down.
The largest feathers are the “primaries”,which are at the end of the wing.There are 10 primaries at the end of each wing,but the end 5 are the largest. They give lift and stability. Notice the shape of the primaries on his lefthand side. See how thin the shaft is and further down it widens. I’ve talked to a friend who is a bird expert about this “thinning”. He believes they are normally this shape but I wonder if its because of wearing? During moulting season (August) they loose many feathers but also do loose them individually during the year. There are smaller feathers growing underneath in behind that will eventually replace the feather being used for flight.
UPDATE – It appears the thinning of the feathers near the end of the wing are normal and not wearing. This narrowing is called “Emargination” on the anterior side and “Notch” on the posterior side. It allows for extra lift and maneuverability.