Flightless birds were more common before human-driven extinctions

Dr Ferran Sayol and Professor Tim Blackburn (both UCL Biosciences) discuss their new study, which found there would be at least four times as many flightless bird species on Earth today if it were not for human influences. When the first humans started to colonise all the regions of the world, many species went extinct. Some were directly hunted to extinction, others saw their habitats destroyed, and yet more were wiped out by the introduction of non-native predators like rats. One of the consequences of human-driven extinctions is the distortion of biological patterns. Studying how evolution works is more challenging if humans have caused many species to go extinct, because the diversity we see today may not be representative of how evolution worked up to the point that we came on the scene. We know that evolution can sometimes take strange paths. For instance, while birds are acknowledged masters of flight, some have nevertheless abandoned this ability for life on the ground.