A typical nest is around 5 feet in diameter. Eagles often use the same nest year after year. Over the years, some nests become enormous, as much as 9 feet in diameter, weighing two tons. Even when a nest tree falls or a strong wind blows a nest down, the established pair usually rebuilds at or near the site within a few weeks if it is near the breeding season. The nest may be built in a tree, on a cliff, or even on the ground if there are no other options available.
Eagles are territorial during nesting season.
They will keep other eagles out of their own nesting area. Their nesting territory is usually one to two square miles. Sexual maturity - An eagle reaches sexual maturity at around four or five years of age. At that time, the eagle's energies become concentrated on the effort of finding a mate and raising offspring. Bald eagles mate for life, but when one dies, the survivor will not hesitate to accept a new mate.