The Bald Eagle was chosen as the emblem of the United States of America June 20,1782, because of its long life, great strength and majestic looks, and because it was then believed to exist only on this continent. 

"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, thought, and an opportunity for a full and free expansion into the boundless space of the future." Maude M. Grant

Bald Eagles may have numbered half a million before European settlers first arrived on this continent.   As the human population grew, the eagle population declined.  The food supplies decreased for the eagles, because the people hunted and fished over a broad area, and early ranchers and farmers shot bald eagles out of an erroneous fear the eagles would prey on their livestock.   Humans and eagles competed for the same food, and humans had the advantage with the weapons at their disposal.  As human population expanded westward, the natural habitat of the eagles was destroyed, leaving them fewer places to hunt and nest  which caused the population to decline sharply by the late 1800's.

In 1940 the Bald Eagle Act was passed.  This reduced the harassment by humans, and the eagle populations began to recover until the use of DDT and other pesticides began their wide use.  The DDT poison harmed both the adult birds and the eggs that they laid.  The egg shells became too thin to withstand the incubation period, and were often crushed.  Eggs that were not crushed during incubation often did not hatch, due to the high levels of DDT and its derivatives.  Large quantities of DDT were discovered in the fatty tissues of dead bald eagles, which may have caused them to become infertile.  More than 100,000 bald eagles were killed in Alaska from 1917 to 1953.  Alaskan salmon fisherman feared they were a threat to the salmon population. Between 1917 and 1953, the Alaskan legislature endorsed bounties on bald eagles – seen as a threat to salmon runs – resulting in over 128,000 being killed.

In 1967 there were as few as 450 nesting pairs of bald eagles left in the lower 48 states and during that same year the "Bald Eagles" were officially declared an endangered species in all areas of the United States south of the 40th parallel, under a law that preceded the Endangered Species Act of 1973.  The Endangered Species Act was signed into law in 1973 by President Richard Nixon.  This landmark legislation is regarded as one of the most comprehensive and important wildlife conservation laws in the world.  On July 4, 1976, the US Fish and Wildlife Service officially listed the bald eagle as a national endangered species.

.As of May 15, 2004 it has officially been announced by the Bush Administration that the bald eagle's numbers have increased to approximately 7678 pairs currently in the United States and they have been downgraded from an Endangered to Threatened Species.