The common ancestor of all modern birds lived in South America some 95 million years ago.

Birds inhabit every continent, and are among the most diverse vertebrate groups on Earth. To chart birds' rise and spread, Santiago Claramunt and Joel Cracraft at the American Museum of Natural History in New York created an evolutionary tree based on DNA sequences from 230 bird species and fossil records for 130 extinct species.

They found that bird diversity expanded rapidly after the demise of dinosaurs some 66 million years ago, dispersing along two primary routes. From South America, birds moved into North America, spread to Eurasia through the Arctic and then on to Africa. Birds arrived in Australia by way of Antarctica.

Sci. Adv. 1, e1501005 (2015)