(CNN)A previously extinct species of bird returned from the dead, reclaiming the island it previously lived on and re-evolving itself back into existence, scientists have said.
Extinct species of bird came back from the dead, scientists find
The white-throated rail colonized the Aldabra Atoll in the Indian Ocean and evolved to become flightless, before being completely wiped out when the island disappeared below the sea around 136,000 years ago.
But researchers found similar fossils from before and after that event, showing that the chicken-sized bird re-appeared when sea levels fell again a few thousand years later, re-colonized the island and again lost the ability to fly.
The flightless rail can be found on Aldabra to this day.
The extremely rare process is known as iterative evolution -- the repeated evolution of a species from the same ancestor at different times in history.
The team's study, published in the Zoological Journal of the Linnean Society, marks the first time the process has been seen in rails, and is one of the "most significant" instances ever found in birds, according to the authors.
"We know of no other example in rails, or of birds in general, that demonstrates this phenomenon so evidently," co-author David Martill, of the University of Portsmouth, said in a statement.
The rail's return to Aldabra is not the only time in its lineage that it has escaped extinction.
The parent species of the rail, indigenous to Madagascar, would frequently see its population explode, forcing the birds to migrate in great numbers from the island off the coast of East Africa.
Many of those that flew north or south drowned in the Indian Ocean, and those that went west landed in Africa, where they were eaten by predators.
But the lucky few who went east ended up on islands including Mauritius, Réunion and Aldabra, the latter of which was studied by the researchers.