The extinct ancient bird revived from the dead

Repeat evolution has helped an ancient bird to reappear in the Indian Ocean and survive today.

Aldabra atoll in the Indian Ocean used to be home to hundreds of species, including the giant Aldabra turtle. But 136,000 years ago, a great flood flooded the entire island, destroying all life, including the white-necked chicken (Aldabra rail) . Then they regenerated and were the last remaining flying bird in the Indian Ocean today.

White-necked chicken is the last flying bird in the Indian Ocean.(Photo: IFL Science).

The cause of this strange phenomenon is a rare natural process called repeating evolution. Thousands of years ago, the white-collar Madagascar chicken (Dryolimnas cuvieri) migrated to Mauritius, Reunion, and Aldabra atolls. There, due to the absence of predators, they lost their ability to fly, forming a new subspecies called the Aldabra chicken (Dryolimnas cuvieri aldabranus).

Then, about 136,000 years ago, the big flood wiped the water chickens from atolls. Without flying wings, they could not escape. But 100,000 years ago, the Ice Age made sea levels fall, Aldabra once again became a suitable place to live. Therefore, water birds flew from Madagascar to atolls. Because there are no predators, they continue to lose their ability to fly.

Madagascar's chicken evolved into two different flightless species for several thousand years. That is quite unusual. Scientists from the University of Portsmouth and the Museum of Natural History in the UK draw this conclusion after analyzing water fossils before and after the flooding event. They found that both species cannot fly.

"This situation seems unexpected, but water chickens are enduring settlers on isolated islands and can evolve quickly in the direction of losing their ability if conditions are right. of Dryolimnas from Magagascar to distant Aldabra Island occurred on many occasions, " the research team reported in the Linnaean Zoology magazine.

The researchers recorded a species of iguanas and many lizards also invaded the island, but were largely destroyed by the presence of invasive black mice. The new study marks the first time that repeated evolution has been found in water birds in particular and in the bird world in general.