More than 99% of birds can fly. But that still leaves many species that evolved to be flightless, including penguins, ostriches, and kiwi birds. In a study in the journal Evolution, researchers ...

Birds can fly— at least, most of them can. Flightless birds like penguins and ostriches have evolved lifestyles that don’t require flight. However, there’s a lot that scientists don’t know about how ...