Jingmai O’Connor, a paleontologist at Chicago’s Field Museum, tells the New York Times’ Asher Elbein.That’s because fossils of Archaeopteryx, which are considered by many to be the oldest known birds,

Flying dinosaur fossil with intact feathers reveals how first birds took flight - Researchers say set of never-before-seen feathers on upper arm proved key to Archaeopteryx’s flight

A Chicago fossil of Archaeopteryx uncovers unknown features, supporting theories of bird evolution from dinosaurs and highlighting its unique flight adaptations.