Birds had to learn to fly all over again after the asteroid apocalypse that killed the dinosaurs 66 million years ago

Bird species had to learn to fly all over again, after the colossal asteroid that wiped out the dinosaurs some 66 million years ago also grounded all avian life.

That's the finding of new research that sheds new light on how bird species survived the devastating asteroid impact that ended the reign of the dinosaurs, according to Daily Mail.

Scientists believe the asteroid also triggered the destruction of forests across the globe. With their natural habitat destroyed, tree-dwelling bird species soon died out.

Only avian species that lived on the ground were able to survive the Cretaceous-Paleogene mass extinction, known as K-Pg.

Emerging from the ashes of the cataclysm were these larger species of land dwelling birds, equivalent to today's emus and ostriches.

'We drew on a variety of approaches to stitch this story together,' says lead author Daniel Field.

'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.'

Scientists were able to confirm the collapse of global forests in the wake of the asteroid impact by using plant fossil records.

Study coauthor Antoine Bercovici, a paleobotanist, collected data on fossil spore and pollen counts found around the world.

He found that in a layer formed during the first thousand years after the impact, most of the spores come from just two species of fern.

'This fern spike represents evidence of "disaster flora," where pioneer species are rapidly recolonizing open ground, ' Bercovici said

It could have taken thousands of years for mature forests to return, the researchers claim.

Modern bird species were also studied for the research paper, to determine how environment has shaped their evolutionary history.

It concluded that the common ancestor to all living bird species lived on the ground.

There were many tree-dwelling bird species living during the age of the dinosaurs.

However, these species were unable to survive the harsh new landscape created by the asteroid, and did not give rise to any of the modern-day species we know.

Dr Field said: 'Today, birds are the most diverse and globally widespread group of terrestrial vertebrate animals – there are nearly 11,000 living species.

'Only a handful of ancestral bird lineages succeeded in surviving the K-Pg mass extinction event 66 million years ago, and all of today's amazing living bird diversity can be traced to these ancient survivors.'

In future, the researchers want to determine the exact timing of the forest recovery on Earth, and the diversification in species of birdlife that followed.

'We are working hard to shed new light on this murky portion of the fossil record, which promises to tell us a lot about how birds and other animal groups survived – then thrived – following the extinction of T. rex and Triceratops,' Dr Field added.