Thunderbirds were gigantic mutie eagles that inhabit the Canadian town of Thunder Bay. They are large enough to carry off a full-grown buffalo, and their claws and beaks are strong enough to tear through metal. Additionally, their scales are hard as iron, making them very hard to kill. (Hell Road Warriors)
Thunderbird was a term used in cryptozoology to describe large, bird-like creatures, generally identified with the Thunderbird of Native American tradition. Similar cryptids reported in the Old World are often called Rocs. Thunderbirds are regarded by a small number of researchers as having lizard features like the extinct pterosaurs such as Pteranodon. Reports of Thunderbird sightings go back centuries, and the fossil record does show that giant birds (teratorns) with wingspans between 12 and 18 ft (3.7 and 5.5 m) were likely contemporary with early man. Today the creature is generally regarded as a myth.