Flightless steamer ducks walking in the Falkland Islands Visions from Earth/Alamy
From ostriches to kakapo parrots to flightless ducks, birds have lost the ability to fly many times. But some groups of birds end up grounded more often than others, and now it seems that those that moult all their flight feathers from both wings at once may be predisposed to evolving flightlessness.
Ryan Terrill at Occidental College in Los Angeles, California, was fascinated by moulting, the process by which birds shed and replace old feathers. As a graduate student at Louisiana State…
Article amended on 2 December 2020
We clarified which feathers flightless birds lose simultaneously
