Small, swift and flightless: The secret life of World's tiniest non-flying bird found on an ‘inaccessible’ island

(Image: Brian Gratwicke)

Hidden on a remote island in the South Atlantic, a small bird exists without wings to carry it aloft. The Inaccessible Island rail does not need to fly, and it manages to exist with remarkable success.

Weighing less than a golf ball and merely six inches in length, the Inaccessible Island rail is the world's smallest flightless bird. Found only on Inaccessible Island, part of the Tristan da Cunha archipelago, this elusive bird thrives far from human reach. The island, just five and a half square miles in size, is shaped by sharp cliffs and fierce seas. These natural defences have protected its wildlife from human damage and invasive species.

The rail hides in thick grass and ferns, darting quickly through the undergrowth. Though it cannot fly, it runs swiftly to avoid seabird predators. Its ancestors likely flew in by accident during a storm. Over generations, they lost the need to fly and slowly evolved into the compact bird seen today.

Despite living in one of the world’s most remote spots, the rail is listed as vulnerable. The entire population, estimated at 5,000 to 10,000, depends on the stability of this single island. The threat of climate change or accidental introduction of predators remains a worry for scientists who closely monitor the bird’s fate.

Flightless birds have had a difficult past. A 2020 study found that of the 581 bird species lost to extinction, nearly 30% were flightless. This is alarming considering flightless birds make up only a tiny portion of all bird species.

Nevertheless, a few species persist. The Galápagos flightless cormorant employs its stumpy wings to dive instead of fly. With fewer than 1,400 remaining, it is still vulnerable but stable due to conservation. In Tasmania, the native-hen runs at a speed of as much as 31 miles per hour. Although it cannot fly, it thrives in the grasslands and wetlands of the island.

New Zealand's weka is another flightless bird that is curious and endearing. Frequently found rooting around camps or foraging for food in the wild, the rail-sized bird is smart and resourceful. Some groups of wekas are in good health, but others are under threat from predators and habitat loss.

Flightless birds are more than curiosities of evolution. They tell us about how the combination of isolation and adaptation can create life in surprising ways. Yet many species remain vulnerable, with limited ranges and specialised habitats.

As long as remote islands stay protected and predators are kept away, birds like the Inaccessible Island rail may continue to thrive. But their survival hangs in the balance, reminding us of how quickly unique creatures can vanish when the world closes in.