Flightless Rail

Smallest island dwelling flightless bird got there how?  According to ScienceDaily 1 November 2018 and Science Alert 7 November 2018 and Molecular Phylogenetics and Evolution, doi: 10.1016/j.ympev.2018.10.007, the world’s smallest flightless bird lives on a small island in the South Atlantic named Inaccessible Island. Not surprisingly it has been named the Inaccessible Island Rail.

Since it cannot fly, there has always been some debate on how it got to this remote place.  The bird was originally named Atlantisia rogersi by Percy Lowe a century ago, who classified it as belonging to a separate genus.  He suggested the bird walked to Inaccessible Island via land bridges which no longer exist.  But a study of its DNA by scientists at Lund University has now shown the bird is closely related to the dot winged crake of South America and the black rail, now found in North and South America.  Both these birds can fly and the scientists suggest the Inaccessible Island rail’s ancestors flew to the island and lost their ability to fly after that.

According to Martin Stervander, who led the study, “The fact that Lowe’s theory was incorrect came as no surprise. Using DNA, we can prove that the ancestors of the Inaccessible Island rail flew to Inaccessible Island from South America about 1.5 million years ago.”

He went on to explain, “The bird has not had any natural enemies on the island and has not needed to fly in order to escape predators. Its ability to fly has therefore been reduced and ultimately lost through natural selection and evolution over thousands of years.”

Science Alert, ScienceDaily

Editorial Comment:  The scientists are probably right in suggesting the ancestors of this small bird originally flew to the island, rather than walked thousands of miles. Then some of the offspring must have suffered a mutation that diminished their wings, but didn’t stop them breeding.  This can happen in one generation as we’ve seen for flightless ducks in NZ. It does not need thousands of years.  The flightless birds therefore remained on the island and established a population, when their ‘still flying’ cousins moved on.

The flightless birds may have survived simply because there were no predators that could kill them on the island, but note well: losing the ability to fly is not evolution.  Losing any function is degeneration, and creatures that experience such a change usually only survive in protected places.  In any other places, natural selection would ‘weed’ them out.  As such, all flightless birds are a reminder that change is real in the living world, but the changes we observe or infer are part of a downhill process that started when God’s original very good world was corrupted by human sin and God’s judgement.

The wings of flightless birds are considered to be examples of vestigial organs, and therefore evolution.  For a proper understanding of vestigial organs, including flightless birds see our article Vestigial Organs. PDF here.

As to claiming the rail lost its wings 1.5 million years ago, such an idea comes from only from assumptions about mutation rates and evolutionary trees.

Photo of Inaccessible Island Rail Brian Gratwicke Creative Commons (CC BY 2.0)

Evidence News vol. 18 No. 17
21 November 2018
Creation Research Australia

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