The ground-dwelling birds that survived would not have had an easy existence. The aftereffects of the Chicxulub impact remain debated, with some scientists advocating that soot within the atmosphere blocked out the sun sufficiently to drive global cooling; others suggest that carbon released from the Earth's crust into the atmosphere upon the asteroid's impact, as well as carbon from wildfires, had a warming effect. Following the cataclysm, these survivors rapidly evolved into most of the lineages of modern birds we are familiar with today, according to paleontologists led by Daniel Field at the University of Bath in the United Kingdom.
Furthermore, an analysis of the most common fossil birds of the late Cretaceous-a primitive group known as the enantiornithes-suggests most were tree dwelling.
With no more perches, the perching birds went extinct.
This is because the impact and its after-effects decimated the planet's forests, leading to the extinction of all tree-dwelling birds, according to an global team of researchers. Acid rain killed off even more vegetation.
Their fossils expose that the ground-dwelling birds had long, strong legs, like those of a kiwi or an emu, absolutely nothing like the fragile legs of setting down birds. Lots of small-bodied birds today consume pests, and this quality can be traced to the enduring birds 66 million years earlier.
"The end-Cretaceous event is the fifth mass extinction - we're in the sixth", said Dunn.
However the ground-dwelling birds that endured brought a long lasting tradition beyond the tinamous. "Only a handful of ancestral bird lineages succeeded in surviving the mass extinction event 66 million years ago, and all of today's unbelievable living bird diversity can be traced to these ancient survivors".
" Today, birds are the most varied and internationally prevalent group of terrestrial vertebrate animals- there are nearly 11,000 living types", Field stated in a declaration. That's because ferns don't sprout from seeds, but from spores, which are much smaller-just a single cell.
"This fern spike represents evidence of 'disaster flora, ' where pioneer species are rapidly recolonizing open ground, such as seen today when ferns recolonize lava flows in Hawaii or landslides after volcanic eruptions", Bercovici says.
So the length of time would it take the ferns to prosper?
"Teasing these stories from the rock record is a challenge when the action took place over 66 million years ago, over a relatively short period of time", said Dr Field, who led a team of UK, US and Swedish researchers.
Studying whole paleoecosystems shows how life on Earth has evolved through all the trials and tribulations of the past, Dunn said in an email.
"If I were to draw a line under the lessons of this study for the modern era, it would be to contemplate the idea that what we are doing in our lifetimes will affect the Earth for the next 100,000 years, which is pretty daunting", MacLeod added.