In native mythology, the thunderbird is able to cause thunder and is able to stir the wind by simply beating its wings. The thunderbird is also able to generate sheet lightning by blinking its eyes, while individual bolts are made by glowing snakes that it carries with it. A famous story of the thunderbird is called Thunderbird and Whale.
In cryptozoology, thunderbirds are unnaturally large bird sighted all over North America. In an early sighting of the thunderbird in 1890, two cowboys killed what they described as a very large bird, however their description of the entity was similar to that of a pterodactyl.
In 1977, three young children were playing in the backyard when two large birds approached and proceeded to chase the three boys. One boy was seized by the shoulders and was lifted about two feet above ground for a short period of time before being released.
One theory proposed by scientists is that the large birds were in fact Steller's sea eagle, with a wingspan of 6-8 ft.
Some say that the thunderbird of mythology was an exaggeration of large birds such as the bald eagle.