Birds 'had to rediscover flight' after dinosaurs
Birds had to rediscover flight all over again after the meteor strike that killed off the dinosaurs, scientists believe.
The cataclysm 66 million years ago not only wiped out Tyrannosaurus rex and his relatives, but also tree-living flying birds.
The only ones to survive were flightless species that lived on the ground and every bird alive today is descended from these emu-like ancestors, scientists believe.
Co-author Dr Daniel Field, from Bath University, said: "The ancestors of modern tree-dwelling birds did not move into the trees until the forests had recovered."
The 10 to 14km-wide meteor, which may have been an asteroid or comet, struck the Earth off the coast of Mexico, releasing a million times more energy than the largest atomic bomb.
Fossil records show evidence of mass deforestation and birds surviving the end of the Cretaceous period had long sturdy legs made for living on the ground.