Almost every Native American tribe tells of a legendary Thunderbird. Most people are familiar with Native American folklore and traditions about Thunderbirds, but cryptozoologists have also collected current sightings and case material. Mark A. Hall's Thunderbirds - America's Living Legends of Giant Birds (2004) is a detailed discussion of modern sightings from Appalachia and the Black Forest of Pennsylvania to the plains of Illinois and the Ozarks of Arkansas.Each year in late March, early April. July, and August, from the Ozarks down the Ohio River Valley and into the Appalachian Mountains, an irregular and noticeable migration of big birds seems to be occurring, and these may be Thunderbirds. Similar appearances in the western mountain states show a comparable pattern.
But what could these creatures be? From their descriptions as large dark-colored, gliding birds with wingspans over fifteen feet wide, Thunderbirds seem to be associated with the largest-known soaring birds accepted by ornithologists called the condors. There is two condors, the Andean Condor (Vulturgryphus) and California Condor (Gymnogyps californinus) that could be possibilities. The Andean Condor is the world's largest flying bird with a wingspan of about ten feet ( some reported specimens have reach a twelve foot wingspan) is glossy black with white upper-wing coverts, a bald head, and a white collar of feathers around its neck. They live in the Andes Mountains, from Columbia south to Tierra del Fuego between the 7,000 to the 16,000 foot level. The California Condor is smaller than the Andean Condor. However, with a nine foot wingspan, it is the largest flying bird in North America. It is sooty black but lacks the white neck collar.
The most likely zoological candidates for Thunderbirds may be the recently extinct Teratorns. Alan Feduccia , author of The Age of Birds (1986) said, "Perhaps the most remarkable of Ice Age vulturine birds found in the New World were the Teratorns. The very common Teratornis merriami had a wingspan of eleven to twelve feet, and Teratornis incredibilis known from deposits in Nevada and California, had a wingspan that reach up to seventeen feet. But the largest of them was an Argentine fossil that was nearly twice the size of Teratornis merriami. It stood about five feet tall and had a wingspan of about twenty-four feet. It is the largest flying bird known to science." The bones of the Teratorns have turned up in deposits from California to Florida. Apparently they were found throughout the United States, as well as the northern parts of Mexico. This fits nicely with the reports of the Thunderbird, which are centered in the same geographical areas. Did the Teratorns look like Thunderbirds? Interestingly, National Geographic have shown Teratorns as being condor-like with white ruffs around their necks, obviously modeling them after the Andean , not the California Condor. But the fossils they found of Teratorns, really do not show what their feathers looked like?
For more information on Thunderbirds, Teratorns, and condors go http://www.wikipedia.com .