Thunderbird, Wrath of the Skies

In Cryptozoology, "Thunderbird" is a term associated to winged creatures of large dimensions, typically identified with the Thunderbird of the Native Americans traditions.
The name seems to originate from the thunder-like sound that the flapping of the wings of these giant birds would produce, but also from its migrating to the North-West of the Pacific during the rain season. There are similar cryptids reported by witnesses in the Eurasian continent, that are called "Rocs."
According to the witnesses the Thunderbirds look like reptilian saurians just like the now extinct Pteranodons. They sport a tuft of white hair around their neck, and a bald head. Their wings span from 9 to 70 feet long, although most accounts speak of a 10-18 feet long wing span. The Thunderbirds are carnivorous, feeding off mammals and carcasses of animals. It is reported that, in the West Coast of the Americas it can attack whales as well, grabbing them with their claws and out of water. The Thunderbird nests over the highest peaks and rarely attacks humans. In some instances people reported to have seen this giant bird clawing a human being, dragging him away.

The Thunderbird is distributed all across North America, the most notable legends coming from Moung Edgecumbe, Alaska; Tombstone, Arizona; Alpena, Michigan; Whiteside Mountains, North Carolina; Blount County, Tennessee; Thunder Mountains, Wisconsin; Southern Alberta, Canada.
More rare are sightings from the Western Indies and South America.
The encounters with the Thunderbirds date back centuries, and the fossils of Teratorns or giant birds found in various locations onlu reinforce the idea that they lived along with the first humans.

However today the Thunderbirds belong to mythology, but are searched and studied by Cryptozoology. As such, it is essential to begin the investigation by exploring the legends in the attempt to understand the possible origin of this creature.
All the Indian tribes of North America, especially those that lived along the Pacific coastline as well as near the Great Lakes region have passed on stories about the existence of giant birds of prey. Some of these legends tell about these birds being so large and mighty that, when flapping their wings, the sound produced was the same as a thunder, while lightnings would come out of their eyes and water gushed out of their back becoming rain. Native Americans used the Thunderbird to explain some natural phenomena such as storms and blizzards. However, for as much as mighty and dangerous they were, the Thunderbirds were revered as beneficial spirits of nature that in some instances helped the tribes to find food during periods of famine.