While the thunderbird is primarily a mythical figure, there have been modern reports that seem to coincide with the legendary descriptions of this creature. One of the most famous of these sightings occurred in 1977 in Alton, Illinois. A number of witnesses reported seeing a gigantic bird with a wingspan far beyond the size of any known bird species in North America. Some of these sightings were accompanied by descriptions of the bird’s dark color, sharp talons, and intimidating presence. Many cryptozoologists and enthusiasts have claimed these sightings are evidence of an undiscovered species of prehistoric bird, possibly a surviving pterosaur.
Some cryptozoologists speculate that the thunderbird may be a surviving species of prehistoric bird or pterosaur, an ancient flying reptile. Proponents of this theory suggest that such creatures could have lived during the time of the dinosaurs and survived into modern times, hiding in remote areas or going undetected due to their elusive nature. The most popular candidate for this theory is the Pteranodon, a massive flying reptile with a wingspan of up to 33 feet. Some of the reported thunderbird sightings, particularly those involving large, winged creatures capable of carrying off small animals, could be explained by such a creature’s presence.
Some researchers believe the thunderbird sightings could be cases of misidentified birds, like the condor, bald eagle, or vulture, that were described as larger than they actually are. The California condor, for example, has a wingspan that can exceed 9 feet, which could seem much larger when seen from a distance or in certain conditions. The sightings of thunderbirds may simply be an exaggeration of natural occurrences.
The thunderbird shares similarities with other large, winged cryptids like the Jersey Devil and the Mokele-Mbembe. While these creatures are very different in appearance and origins, they all share the characteristic of being elusive, large, and often described as predatory. Cryptozoologists have drawn parallels between these creatures, suggesting that they may be remnants of prehistoric creatures that somehow managed to evade detection or extinction.