Islands are known for producing unusual animals, and a newly studied extinct bird from Hawaii may be one of the strangest yet.
Scientists have discovered that a flightless Hawaiian ibis called Apteribis had unusually small eyes, suggesting it may have lived a mostly nocturnal life.
The research, conducted by an international team from the University of Lethbridge in Canada and Flinders University in Australia, sheds light on how island environments can dramatically reshape evolution.
The scientists made the discovery while studying fossilized skulls of Apteribis, a bird that once lived on the Hawaiian Islands but is now extinct.
Although it was related to the modern Australian white ibis, this island species looked and behaved very differently. Like other ibises, it likely used its long, curved beak to probe soil and mud for hidden prey such as insects and small invertebrates.
However, its vision appears to have been far weaker than that of its living relatives.
To understand how unusual this bird was, researchers examined skulls from most living ibis species and created detailed 3D models of their brains using advanced imaging techniques.
When they compared these with the fossil skull of Apteribis, they found that the areas linked to vision—including the eye sockets, optic nerve region, and parts of the brain that process visual information—were dramatically reduced. Such extreme changes are rare and are usually seen only in birds that rely very little on sight.
This finding suggests that the Hawaiian ibis was probably active at night. Other birds with similarly reduced visual systems, such as the kiwi in New Zealand and the night parrot in Australia, are known to forage after dark. Living at night may have helped the ibis avoid daytime heat and competition, while allowing it to hunt prey that was also active in the dark.
The unique conditions of island life likely played a major role in shaping this bird. Hawaii originally had no land mammals that preyed on birds, making it a relatively safe place for large birds to live on the ground.
Over time, species like Apteribis lost the ability to fly because it was no longer necessary for survival. In such an environment, sharp eyesight may have become less important, especially if food could be found by touch using the beak.
The ibis may also have adapted to the behavior of its prey. Ancient Hawaii was home to many nocturnal animals, including flightless crickets and land snails, which would have provided a steady nighttime food source. Hunting in the dark would have given the bird access to abundant food with less competition.
Sadly, Apteribis eventually disappeared, likely due to a combination of climate changes, habitat shifts, and the arrival of humans on the islands. Its story highlights how much biodiversity has already been lost and how many unique species vanished before scientists could study them.
This unusual ibis shows that evolution can produce similar solutions in distant places. Just as the kiwi evolved in New Zealand, a night-roaming, ground-dwelling bird also emerged in Hawaii.
Discoveries like this help scientists better understand how animals adapt to isolated environments—and how fragile those ecosystems can be.
