When most people think of birds, what common attributes typically come to mind? Many will cite a bird’s ability to fly, sing and use its feathered wings to take flight. So it may seem a bit strange that included in the more than 10,000 species of birds in the world today is a group that literally cannot fly or sing, and whose wings are more fluff than feather. These are the ratites: the ostrich, emu, rhea, kiwi and cassowary. How and why these birds abandoned flight has puzzled scientists since Darwin’s time, but as this Nature program shows, DNA and dedicated research are helping to solve these mysteries.