The Arctic might evoke images of polar bears and seals, but 73m years ago it was a dinosaur stomping ground.
While the earliest birds emerged in the Late Jurassic, about 150m years ago, the delicate nature of bird bones means such animals are rare in the fossil record.
“Prior to this work, and with the exception of a few footprints, bird fossils weren’t known from Alaska,” said Druckenmiller.
“It was literally like panning for gold, except bird bones are our prize,” said Druckemiller.
It suggests the prehistoric birds nesting in the Arctic were close relatives of modern birds.
Despite its association with seals and polar bears, the Arctic was a dinosaur stomping ground 73 million years ago. Fossil hunters now claim that a variety of birds coexisted with these creatures on their territory.
By delaying the date by more than 25 million years, scientists think their finding of more than 50 bird fossils from Alaska’s Prince Creek formation is the earliest proof of birds nesting in polar regions.
According to Lauren Wilson, the work’s first author from Princeton University, “the previous oldest evidence for polar nesting is a penguin colony from the Eocene of Antarctica [that lived about 46.5m years ago].”.
Today, the Arctic is home to more than 200 different species of birds, which the researchers say are important components of the ecosystem, assisting with vital functions like seed dispersal and pollination. Additionally, recent research indicates that their existence is not particularly novel.
The University of Alaska Museum of the North’s director, Prof. Patrick Druckenmiller, who co-authored the study that was published in the journal Science, stated that the new fossils “fill a major gap in our understanding of bird evolution.”.
Because of the fragility of bird bones, birds are uncommon in the fossil record, even though the earliest birds appeared in the Late Jurassic, some 150 million years ago. “Except for a few footprints, bird fossils from Alaska were unknown prior to this work,” Druckenmiller stated.
The team meticulously excavated bones and cleaned and sieved material from small, sandy deposits to isolate tiny fossils, many of which were less than 2mm in size, so the discovery was much more than just fortunate.
According to Druckemiller, “it was literally like panning for gold, except our prize is bird bones.”.
“A large number of the bones were from embryos or hatchlings,” Wilson continued. She claimed that at least one species of bird, which would have resembled a toothed seagull and belonged to the now-extinct group Ichthyornithes, was discovered by the researchers. At least one member of the Hesperornithes, which were toothed, foot-propelled diving birds, was also discovered.
There were a lot of fossils from toothless birds that might have looked like ducks. This is important, the team notes, because traits like toothlessness are characteristic of Neornithes, the group that comprises all extant birds and their most recent common ancestor. It implies that the birds that nested in the Arctic in the past were closely related to birds today.
According to Druckenmiller, the Prince Creek ecosystem 73 million years ago would have had roughly six months of nonstop summer daylight, making it extremely green, much like the Arctic today. Food would have been plentiful as a result. But it would have been cold in the winter.
He stated that although the winters were not as severe as they are now, year-round inhabitants would still have to put up with freezing temperatures, sporadic snowfall, and roughly four months of nonstop winter darkness.
Wilson stated that although the recently found fossils demonstrated that the birds were breeding in the Arctic, it was unclear whether they spent the winter there. She also stated that it was very likely that at least some of the birds were migratory.
Even though the fossils the team found were “absolutely minuscule,” they told a huge story, according to Steve Brusatte, a palaeontology and evolution professor at the University of Edinburgh who was not involved in the work.
“These fossils demonstrate that birds were already essential components of these high-latitude communities many tens of millions of years ago, indicating that these communities are a long-standing Earth history norm rather than a contemporary ecological innovation,” he said.
