Scientists find proof that birds nested in the Arctic alongside dinosaurs

Springtime in the Arctic is a spectacular show of life, as millions of birds gather to nest and raise their young under the midnight sun. Remarkably, this annual ritual traces its roots back much further than previously believed – 73 million years ago.

That’s the conclusion of a recently published study that identifies the oldest known evidence of birds nesting in the polar regions.

The discovery was made in northern Alaska’s Prince Creek Formation. It reveals that several types of birds were already breeding in the Arctic during the Late Cretaceous period, when dinosaurs still ruled the land.

These findings challenge previous assumptions about where and when ancient birds reproduced – and expand the timeline of avian life in Earth’s most extreme environments by more than 25 million years.

“For half of the time they have existed, they have been nesting in the Arctic,” said Lauren Wilson, the study’s lead author and a doctoral student at Princeton University. Wilson completed her master’s degree at the University of Alaska Fairbanks (UAF), where the research began.

Bird fossils rewrite history

Using a collection of over 50 fossilized bird bones and teeth excavated from Alaska’s North Slope, Wilson and her team made an important discovery. They identified several species of birds that appear to have nested in the region.

These included diving birds similar to modern loons, gull-like species, and various duck- and goose-like waterfowl.

The bones representing juveniles – some likely still nest-bound – offer strong evidence that these birds were not merely passing through but breeding in the Arctic.

“Finding bird bones from the Cretaceous is already a very rare thing,” Wilson said. “To find baby bird bones is almost unheard of. That is why these fossils are significant.”

Saving fragile fossil evidence

The mere existence of such delicate remains is extraordinary. Bird bones are lightweight and fragile by design, and juvenile bones are even more prone to destruction over time.

Yet, thanks to meticulous excavation efforts, researchers were able to recover and identify these fossilized traces of ancient avian life.

The fossils were found in the Prince Creek Formation, a remote site along the Colville River renowned for its Cretaceous dinosaur remains.

Until recently, the area was not known for yielding fossil birds. This changed recently, thanks in part to the excavation strategy used by the UAF Museum of the North’s research team.

Tiny bones from Arctic bird fossils

Traditional vertebrate paleontology often focuses on recovering large, visible bones – those of dinosaurs, for example. But the team working at Prince Creek takes a more comprehensive approach.

Alongside the big finds, they also gather large volumes of sediment and screen them for microscopic remains. Researchers then carefully examine these samples under microscopes back at the lab, revealing a world of small, often-overlooked fossils.

“We put Alaska on the map for fossil birds,” said Pat Druckenmiller, the paper’s senior author and director of the University of Alaska Museum of the North. “It wasn’t on anyone’s radar.”

Druckenmiller credits the fine-grained approach with revealing new insights into Cretaceous Arctic ecosystems. The same methods have also led to the discovery of new dinosaur and mammal species in the region.

“In terms of information content, these little bones and teeth are fascinating and provide an incredible depth of understanding of the animals of this time,” Druckenmiller said.

Ancient Arctic bird nursery

The findings show that birds have been using the Arctic as a breeding ground far longer than previously thought.

Earlier evidence of polar bird nesting dated to around 47 million years ago – well after the mass extinction event that wiped out most of Earth’s species, including the non-avian dinosaurs.

The new discovery pushes that timeline back by 25 to 30 million years, deep into the age of dinosaurs.

“The Arctic is considered the nursery for modern birds,” Druckenmiller said. “It’s kind of cool when you go to Creamer’s Field [a well-known stopover for migratory birds in Fairbanks], to know that they have been doing this for 73 million years.”

The origins of modern birds

Beyond expanding the record of avian life in the polar regions, the fossils raise intriguing questions about the origins of modern birds.

Some of the bones appear to belong to Neornithes – the group that includes all living birds. These fossils show skeletal traits exclusive to modern birds. Some even lacked teeth, a feature seen in today’s avian species.

“If they are part of the modern bird group, they would be the oldest such fossils ever found,” Druckenmiller said.

At present, the oldest known Neornithes fossils date to around 69 million years ago. “But it would take us finding a partial or full skeleton to say for sure.”

Why does any of this matter?

The implications of the study go beyond the Arctic. They suggest that ancient birds – despite their small size and delicate physiology – were able to thrive in high-latitude environments long before the polar climates we know today fully developed.

During the Cretaceous, the Arctic was warmer but still experienced seasonal extremes of light and darkness, posing significant challenges for any nesting animals.

That these birds not only survived but reproduced successfully hints at a more complex evolutionary history than previously assumed. It also suggests modern migratory waterfowl echo ancient patterns by returning to northern wetlands each spring to raise their young.

As researchers continue to study the Colville River fossils, they hope to uncover additional material that can confirm the identity and relationships of these Arctic avian pioneers.

For now, the Prince Creek Formation stands as one of the world’s most important sites for understanding the early history of birds. It shows what can be found when scientists search for both big and small bones.

The study is published in the journal Science.

Image Credit:  Gabriel Ugueto

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