Flightless birds more common globally before human-driven extinctions

There would be at least four times as many flightless bird species on Earth today if it were not for human influences, finds a study led by UCL researchers. The study, published in Science Advances , finds that flightlessness evolved much more frequently among birds than would be expected if you only looked at current species. Researchers say their findings show how human-driven extinctions have biased our understanding of evolution. Lead author Dr Ferran Sayol (UCL Centre for Biodiversity & Environment Research and University of Gothenburg, Sweden) said: "Human impacts have substantially altered most ecosystems worldwide, and caused the extinction of hundreds of animal species. "This can distort evolutionary patterns, especially if the characteristics being studied, such as flightlessness in birds, make species more vulnerable to extinction. We get a biased picture of how evolution really happens." For the study, the researchers compiled an exhaustive list of all bird species known to have gone extinct since the rise of humans. They identified 581 bird species that went extinct from the Late Pleistocene (126,000 years ago) to the present, almost all of which were likely due to human influences.