Flying higher than any other bird, they symbolize the indomitable power of the spirit.
The eagle is quite simply the king of the birds. In symblism written or pictorial, it's representative of the mightiest rulers, the highest Gods, and the greatest heroes. In surviving texts from ancient Babylon, the deceased king is borne to the heavens by an eagle. In many instanes, the eagle embodies lofty aspirations and higher spiritual achievement. In other cases, it symbolizes strength and glory and even substitutes for the sun in Arctic and some Indigenous American mythology. Because they are also birds of prey, eagles have come to be associated with clarity of vision and thus insight as well. Adopted as the national bird of the U.S. in 1782.
Eagle eating snake:
The eagle that eats a snake while perched on a nopal cactus appears on the national flag of Mexico. It's derived from the Aztec legend that the capital, Mexico City, was founded according to the command of the sun and war god Huitzilopochtli, who was sometimes represented as an eagle. According to his command, Tenochtitlán, the Aztec capital and antecedent of Mexico City, was founded in C.E. 1325 on a spot where an eagle was seen devouring a snake, ending a long and perilous migration from the Aztec's traditional home of Aztlan to the Valley of Mexico.