After having had the opportunity to witness the flight practice, I decided to go back the next day (July 22, 2011) to the Bald Eagle (Haliaeetus leucocephalus) nest. When I arrived at the nest, there was one juvenile in the nest and another one on a branch nearby. No sign of the third. I thought I heard a juvenile call from the forest east of the nest, but I am not sure.
So, I continued up the trail hoping for some action. There were some pelicans and some hawks on the other side. Eventually, an adult Bald Eagle flew in at high altitude and was harassed by the hawks.
Then (ESP?) I looked upstream and there was this low-flying Bald Eagle juvenile coming my way. It flew just about right over me (top photo). WOW. What a sight.
She (I think it's a she because of the position of the eyesocket relative to the jaw hinge and the eye ridge) flew very confidently. Not high, not fast, no circles, but very confidently. She made several passes including flying to the other side of the river and landing at the top of a tree. The hawks were screeching about and the Bald Eagle left after five minutes or so. She did not seem to be bothered by the hawks "I'm an eagle. You're hawks". But maybe the noise got to her. Even at that distance, the size difference was readily noticeable. I did get some more pictures and then she flew further inland.
The adults were perched on trees about 200-300 m downstream from my position and three or four times one of them flew over and made a brief excursion in the direction in which the juvenile had disappeared. To check things out, I suppose.
At some time, a Red-tailed Hawk (Buteo jamaicensis) flew out, quite low, from the direction in which the juvenile Bald Eagle had disappeared. Whether it was one of the harassing hawks, I don't know.
I did go back to the nest at some time, just to check it out. Still two juveniles there, so only one flying around at that time.