Endangered species of flightless birds

University of Gothenburg

Bird species that have lost the ability to fly through evolution have become extinct more often than birds that have retained their ability to fly, according to new research from the University of Gothenburg.

Today we know that human influence on the environment has caused the death of a large number of plants and animals. Human impact has radically changed ecosystems and, globally, has led to the extinction of hundreds of animal species.

One consequence of this is that the biological samples have become distorted. This, in turn, means that researchers have difficulty interpreting current data on species diversity – the variations of species within an ecosystem or area.

“Studying human-caused extinction of species can influence our understanding of evolution and help us better understand the loss of species not caused by chance,” says Søren Faurby, senior author behind the new study and a researcher at the University. of Gothenburg.

Together with his research colleagues, he studied a broader evolutionary transition: the development of the absence of flight among birds. For the first time, a study of this transition includes data from all known flightless species brought to extinction by man.

“We found that, in many cases, the extinctions had anthropogenic origins, effects attributable to human activities.

Flightless birds are more common than researchers believed

Birds that have lost the ability to fly are a more common phenomenon than research has hypothesized so far, according to the study. These species were then influenced by human activities.

“Many bird species can develop the inability to fly in environments without large predators, such as on islands, but they also become easier prey for both humans and animals, such as rats and cats,” says Ferran Sayol, l lead author of this study and previously a postdoctoral researcher at the University of Gothenburg.

The researchers compiled a list of 581 bird species from 85 different families that have gone extinct over the past 126,000 years.

“Based on the morphological descriptions, we determined that 166 of these species lacked the ability to fly. This equates to 29% of extinct bird species. Currently, there are only 60 species of flightless birds living. If we add the 166 species that have become extinct, this amounts to 226 extinct and extinct flightless bird species.

The study shows that by adding these extinct birds to the global picture of bird diversity, it becomes clear that the inability to fly has developed at least four times as often as if researchers were only looking at living species.

“We show that the development of flightlessness in birds is a widespread phenomenon. If humans hadn’t caused some of these extinctions, we would still have shared the planet with more than 150 independently developed groups of flightless birds. Unfortunately, only 60[Accent1] of these remain “, says Ferran Sayol.