from the book, "Petrified Lightning"
A survey of birds' nests of the world clearly shows that most species build a new nest for their eggs each year. Moreover, some will build two or three new homes for their offsprings in a single season.
Not so the bald eagle. This bird uses the same nest year after year. It chooses only one mate for its whole lifetime and with that mate builds a single nest high in a tall tree. Here the pair stays until death does them part. The pair, mostly the male, will keep this single nest constantly in repair by adding more and more fresh nesting material. Constantly built upon, in a few years the nest will become gigantic in size and weigh as much as 2,000 pounds. Scientists have little trouble spotting the large, sturdy nest of bald eagles. They refer to the nest as an aerie.
Offspring, once they leave the nest, never return; they would be looked upon as intruders and dealt with quite harshly. A pair may even kill their old offspring in trying to protect new hatchlings. But if one eagle were to die, the other would seek out another mate. The nest is completely abandoned and a new nest is built and will eventually grow to the same or greater size.
Eagles, by the way, have a unique mating ritual. Seeking a mate, the male will fly around the female, showing off his abilities in specialized flight. Impressed, the female will extend her clawed feet, which the male will lock onto with his clawed feet. Together they will fall, turning and twisting over and over and never relaxing their grip on each other or making use of their wings. When just about ready to hit the ground, they release each other's feet. Using their wings to stop their fall, they fly alongside each other for a while. They appear to have been testing each other's courage and skill. Having passed the test, they are now mated for life.