Fossil illuminates ancestry of swifts and hummingbirds

Diminutive size came before specialized wings

Two aerial acrobats with very different flying styles probably shared a much less agile common ancestor, a spectacularly preserved bird fossil reveals.

Today’s swifts fly fast and glide gracefully thanks to their lanky, long wings, while their hummingbird relatives use short, bladelike wings to hover. It’s unclear how and when these wing shapes emerged.