The White-Throated Rail is believed to be the last flightless bird in the Indian Ocean.
At two distinct times, separated by thousands of years, ancestors of this species found it’s way to the island of Aldabra. Without any natural predators on the island, the species evolved to become flightless… twice!
The reason the flightless bird went extinct in the first place was because the island was submerged under rising seas. Since the birds couldn’t fly they were all wiped out.
Thousands of years later the sea levels lowered and exposed the island. Rails flew to the island and AGAIN evolved to become flightless.
This process of evolving twice from the same ancestor at different times is called iterative evolution.
This is a monumental discovery, believed to be the only time iterative evolution has been discovered in birds. Part of the problem stems from the lack of fossil evidence… there may be many instances of the phenomenon throughout history but no way to find them.
