Each spring, they repair and refurbish the nest until it meets their approval. These continual additions to the nest enlarge it to enormous proportions. One observed nest measured eight feet in diameter and probably weighed over two tons. If an eagle's nest is destroyed for any reason, they are known to build another very close by. Once the nest has been made eggworthy the female lays one to three eggs, each a day apart.
Incubation begins immediately with the female shouldering most of the nest-sitting duties.
Her mate takes on the responsibility of hunting for both of them while they wait for the first egg to hatch, approximately five to six weeks after it was laid. Once the chicks hatch, they require near-constant attention and protection from the elements, with both parents now sharing the responsibilities. Perhaps the greatest survival challenge for eaglets in the nest comes from each other. Since the eggs are laid a day or two apart, the first-hatching chick will have a head start on second or third chicks. Strangely enough, adults do not try to protect the eaglets from each other.