The hidden rule for flight feathers and how it could reveal which dinosaurs could fly

Scientists examined hundreds of birds in museum collections and found a suite of feather characteristics that all flying birds have in common.

These "rules" provide clues as to how the dinosaur ancestors of modern birds first evolved the ability to fly.

Researchers examined 65 fossil specimens representing 35 different species of feathered dinosaurs and extinct birds.

Our understanding of flight in dinosaurs is just beginning, says O'Connor .

Theropod dinosaurs are one of the most successful vertebrate lineages on our planet.

"We're likely still missing some of the earliest stages of feathered wing evolution," says Kiat .