This 'sea eagle,' the national bird of the United States of America, can be found near open water, a copious food supply, and an old growth forest. Its most important food source is fish and it prefers to nest in tall, mature trees. This large bird can be forty-two inches in length, have a wingspan of eight feet, and have a mass of fifteen pounds. Interestingly enough, the females tend to be significantly larger than the males. Usually living for a score or more, eagles may migrate if their water supply freezes. Mating for life, these birds share the work of raising chicks.