Repeated Evolution of Flightlessness in Dryolimnas Rails



About 240,000 years ago, a flock of leggy birds took off from Madagascar and inhabited the island Aldabra, which is 250 miles away from their origin. As Aldabra is a secluded island, there were no predators that roamed around, eliminating the need for the birds to flee or fly around. This way of life eventually led the birds to lose their ability to fly and overtime, their anatomy has changed, as well. However, this adaptation to their environment may have led to their demise. A big flood washed over the island and wiped out all the birds and every other life that inhabited in that island.

As the world continues to change through time, specifically, changes in sea levels, the island reemerged. Another flock of bird species flew from Madagascar and arrived on the island of Aldabra. Shockingly, scientists reveal that the birds have taken the same pattern in diversion and evolution.

Rails are known to be a species of flying birds. They are often seen skulking for food around marshes. Some species of rails are also known to fly very far from their habitats in search of a new and more hospitable habitat. This trait has is true even for some white-throated rails which have flown out of Madagascar and settled in Aldabra, once again.

A new study documents a new genus of rail that seem to be evolving around the same trajectory of the rail species that occupied the land and was extinct before the new group came to inhabit the land.

"In about 20,000 years or maybe less, the rails will once again evolve as flightless birds," stated Julian Hume, representative of the Natural History Museum in the United Kingdom. Hume added, "the evolution of species can be quick especially when the conditions are right."

According to the research conducted, the fossil evidence presented was similar to that of the rails that were washed off from extinction. The rails epitomize the ability to fly from one island to another considering the distance where they naturally and originally reside. "Their evolution to being flightless birds as they are known for, now have also been shown in evidence on multiple occasions," stated David Martill, co-author of the study.

The results of the study conducted by both Martill and Hume were recently published in the Zoological Journal of the Linnean Society. The evolution of species may not happen in a few years, not even for a few decades or centuries. However, it is important to highlight that this study just shows that the rails are following the same pattern and trajectory in evolution.

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