That means the discovery represents the North American continent's oldest existing bird tracks, the Salt Lake City Deseret News reported. The sandstone slates containing the tracks will eventually be displayed at the Utah Museum of Natural History.
Utah's state paleontologist, James Kirkland, said the tracks "date at the same age as one of the most important discoveries of this century in terms of dinosaurs and birds," a time of change among the Earth's creatures.
John Foster, curator of paleontology at the Museum of Western Colorado, agreed, saying, "To get much older than this, you have to go into the late Jurassic and the (bird) bones that have been discovered in Europe."
Joanna Wright from the University of Colorado-Denver, told the Deseret News it's difficult to determine what kind of feathered creatures made the tracks. "They were small, perhaps the size of shoreline birds we see along the Great Salt Lake," she said. "But we couldn't put them in a family of modern birds because they go back too far."