Washington's Eagle

The Washington's Eagle, also known as the Bird of Washington or the Greater Eagle is a cryptid species of eagle. While now thought to be a case of mistaken identity, if it were real it would have been the largest known bird in North America. If it was a real species of eagle, it is thought that it would be extremely rare or completely extinct.

Background history
The famous ornithologist John James Audubon had apparently had four encounters with this bird, even killing one to put in his book The Birds of America.

While it was originally accepted as a new found species of eagle, it was later believed to be a case of mistaken identity, what was thought to be of a juvenile bald eagle; however, Audubon would have had to gotten the measurements very, very wrong, as the Washington's Eagle's given size dwarfs even an adult bald eagle which sits between 28-40 inches in length with a wingspan of 6.2 feet.