"Aurornis" was roughly the size of a modern pheasant – in length from beak to tail tip. It had claws and a long tail. Its leg bones are similar to those of "Archaeopteryx", but overall its bone structure is more primitive. The absence of larger feathers suggests "A. xui" was unable to fly. If "Aurornis" lived roughly 160 million years ago, this is about ten million years before "Archaeopteryx", which often has been described as the first bird.