A bald eagle’s nest grows with each year of use. They usually start with one of the taller trees in a given area, with a network of strong supporting branches. While the nest may start out only a couple of feet wide, after a few years of use, the nest can grow to more than six feet wide and ten feet deep. The male usually brings nest material to the nest site where the female will arrange it to suit her. Softer material, such as grasses and leaves, will be used to line the center of the nest.
Copulation usually occurs at the nest. The male will simply mount the female to make contact. The whole thing lasts just seconds. After copulation the pair might perch next to each other for a half hour or so, sometimes preening themselves and each other.
Bald eagles generally lay two eggs, although one or three are not that uncommon. The eggs are laid about two days apart and will normally hatch in the same order as they were laid, with approximately the same intervals between hatchings as there were between layings. The eggs are bluish-white, about 3 inches in length, and roughly oval-shaped. Through time, the eggs will discolor until they appear to be more of a mottled, or dirty, white.
Incubation lasts 34 to 36 days with both the male and female birds incubating. Females will incubate the eggs about 60 percent of the time. During incubation, the male will bring food for the female, many times to one of the supporting branches of the nest and she will usually come off the eggs to eat, with the male taking her place on the nest.