Of the 9,700 breeding pairs of Bald Eagles in North America, Florida has the second largest concentration of birds next to Alaska. In early 2011, we made a point of videotaping the young in one particular nest at a location in Sarasota where the birds were used to people watching them. As shown in the photos, female eagles are larger than males, which is typical of raptors in general. Presumably, because a male is smaller than his mate he can pursue different prey. As far as we could tell, the birds we watched fed their chicks mostly fish and an occasional squirrel. Since a breeding pair of Bald Eagles often reuses the same nest for many years, some nests grow to be very large as sticks are annually piled on top.
The nest we watched was located along gulf coast in Sarasota, FL, in an area that supports nesting eagles and Osprey. While incubating eggs, and during the two weeks after the eggs hatched, at least one adult stayed on the nest; afterward, at least one parent looked on while perched in a nearby tree. At three weeks of age, the young eaglets, covered in gray down feathers, stood about a foot high, tall enough to be seen from the ground. By the fifth week, the chicks stood upright as they ripped flesh off prey provided by their parents. The dark, black-tipped contour feathers of the eagle did not erupt until the sixth week of our vigil. Beneath these water repellent feathers, the juveniles were insulated by a thick layer of white feathers made visible whenever the wind blew. Since six week old chicks are nearly full-grown, the parents no longer needed to watch over their family. In fact, when we returned on the eighth week after hatching, both parents were away hunting, presumably to feed their voracious offspring.
When left alone in the nest, the young eaglets spent most of their time sleeping, with occasional bouts of play. As shown in the video, the birds seemed to enjoy standing on the edge of the nest vigorously flapping their wings, usually while facing into the wind. Since wing-flapping is not necessary to acquire the ability to fly, such antics could be interpreted as a form of play, not unlike mock fighting, and plucking pine cones off of nearby branches (see video). According to the literature, young eagles typically leave the nest between their tenth and thirteenth week of age, but remain dependent on their parents for several additional months.