The ancestor of all today’s birds survived the cataclysmic asteroid strike which killed the dinosaurs because it was a quail-like creature which waddled on the ground.
All flying birds died out after the asteroid struck our planet 66 million years ago, causing a global deforestation.
The asteroid is thought to have hit Earth at 40 times the speed of sound – causing an explosion seven billion times bigger than the Hiroshima bomb.
Only birds on the ground were able to survive – and they evolved flight again thousands of years later, according to University of Bath researchers.
The researchers analysed the fossil record – looking at the plants that survived after the asteroid wiped out dinosaurs.
Dr Daniel Field of the University of Bath said: “We drew on a variety of approaches to stitch this story together”.
“We concluded that the devastation of forests in the aftermath of the asteroid impact explains why tree-dwelling birds failed to survive across this extinction event.
“The ancestors of modern tree-dwelling birds did not move into the trees until forests had recovered from the extinction-causing asteroid.”