For all the birds soaring free in the world there are many who lost their ability to fly, particularly on islands with a lack of mammal predators. Kiwis, kakapos and takahe are all exotic species who live on isolated patches of land. Now a new study has shown that island birds are becoming flightless at a faster rate than anyone anticipated, according to the University of New Mexico’s Natalie Wright.
She collected data on 868 species and found that even with island birds that can still fly they are becoming less reliant on their wings. She found their legs were longer and wings were smaller compared to mainland relatives. After investigating nine major bird groups with a variety of lifestyles, body shapes and diets she discovered a similar trend – On smaller islands with fewer mammal predators and birds of prey, birds have relocated energy from their flight muscles to have stronger legs.
Surprising examples included hummingbirds, as they need to hover in front of flowers to collect nectar if they want to survive. Wright said “island hummingbirds look like hummingbirds when they fly” but “they were still reducing their flight muscles and evolving longer legs on islands without predators.” The same applied to kingfishers, honeyeaters, flycatchers and other species dependent on flight.
Wright’s research suggests that island birds might be more vulnerable to predators who’re introduced into the environment. This could also be an indicator of why island birds diversify into a variety of forms. Protecting flightless birds is important because they have the potential to become extinct quickly as evident in the Dodo. Rather than repeat history we should focus on appreciating how unique they are and setting up conservation programs.