Scientists studying wildlife on the island of Aldabra atoll in the Indian Ocean say they have discovered a small species of bird that evolved after extinction 136,000 years ago, according to the Independent. The white-throated rail, which is a bird that does not fly, has gone through an extremely rare process called "iterative evolution" in which evolution repeats. The rail had previously evolved to become flightless before it was extinguished for the first time. Bird species evolved once again, scientists said after comparing fossils of extinct species with those recently discovered on the island. The white throat rail is about the size of a chicken, and originally migrated from Madagascar when the species could fly.