If you were to take a stroll through the Late Jurassic forest, roundabout 150 million years ago, you might spot little feathery dinosaurs hopping through the undergrowth. They’d look like miniature Velociraptor, complete with tiny sickle claws held off the ground. One might even briefly flutter in the air to nab an insect, or take a short glide down off a toppled tree trunk. And that would offer a critical clue to their real identity. They wouldn’t look very different from the famous “raptors”, but these meek dinosaurs mark the beginning of where birds start.

That’s what University of Edinburgh paleontologist Stephen Brusatte and his coauthors found when they looked at the big picture of bird evolution, throwing in a little