When the Chicxulub asteroid struck our planet about 66 million years ago, that resulted in the death of many of Earth’s species, including the mighty dinosaurs who once ruled the world. Plant life also suffered the consequences of this cataclysmic event, as the darkness that enveloped Earth after the asteroid strike deprived plants of their nutrients. However, there were a few species that survived Chicxulub, and when it came to bird species, a new study suggests that it was the ground-based birds in specific that weren’t killed off.
In a study published recently in the journal Current Biology, a team of researchers analyzed bird fossils from the period before the Chicxulub asteroid strike and those from the aftermath of the impact and concluded that ground-dwelling birds were the lucky ones that survived the post-Chicxulub mass extinction. According to BGR, the researchers were also able to determine why this was the case.
Based on foliage fossils that were also analyzed for purposes of the study, the researchers concluded that Chicxulub led to “massive” fires that led to widespread deforestation. This phenomenon, in turn, resulted in birds being unable to nest like they did before the event. As ferns became the dominant form of plant life in North America after the asteroid strike, tree-dwelling birds couldn’t make the right adjustments, while their ground-dwelling equivalents, including those similar to today’s quails, were “better equipped” to such a situation, as BGR noted.
“The ancestors of modern tree-dwelling birds did not move into the trees until the forests had recovered from the extinction-causing asteroid,” said study lead author Daniel Field, a vertebrate paleontologist at the University of Bath.
Field believes that his research on the Chicxulub asteroid strike hints at modern birds having a common ancestor that “was almost certainly a ground-dwelling bird.” As he explained to The Atlantic, this species might not necessarily have been a flightless bird, but rather one similar to the Central and South American tinamou species that often chooses not to fly, despite being able to do so.
Aside from the fires caused by Chicxulub that apparently displaced tree-dwelling birds, there were other factors in place that could have led to ground-dwelling birds surviving the mass extinction. Other researchers have their own theories, such as the evolution of a more advanced digestive tract for certain bird species, or the ability of some species to lay larger eggs.
birds—world's 10,000+ species evolved in the past 66 million years from a few ground-dwelling ancestors—they survived Chicxulub asteroid impact that killed dinosaurs and 75% of all species, raised avg global temp 5°C (9°F) for 100,000 years https://t.co/H58k0sqzPr @CosmosMagazine
— Sara Laughter (@GreenAwakening) May 25, 2018
“Forest loss was only one of several factors working in combination that determined which bird lineages survived,” said Institute of Vertebrate Paleontology and Paleoanthropology researcher Jingmai O’Connor, who was not involved in the study.
“We need to get over this one-answer-for-everything way of thinking,” O’Connor added, as quoted by The Atlantic.
“No one factor caused the end-Cretaceous extinction and similarly no one factor caused the extinctions within [the birds].”
According to The Atlantic, this is something that Field agrees with, as his previous research suggested that smaller birds might have lasted longer because of their ability to find food in “charred, sun-starved landscapes.”