The American Eagle was chosen to be our National Symbol on June 20, 1782. In addition, it's a very beautiful symbol that is thought to represent many of the noble aspects of the United States of America. The American Eagle is majestic, commanding, and strong.
"It is said the eagle was used as a national emblem because, at one of the first battles of the Revolution (which occurred early in the morning) the noise of the struggle awoke the sleeping eagles on the heights and they flew from their nests and circled about over the heads of the fighting men, all the while giving vent to their raucous cries. "They are shrieking for Freedom," said the patriots. Thus the eagle, full of the boundless spirit of freedom, living above the valleys, strong and powerful in his might, has become the national emblem of a country that offers freedom in word and thought and an opportunity for a full and free expansion into the boundless space of the future." --Maude M. Grant