Arctic hatchlings: Study finds birds nested with dinosaurs 73 million years ago

An illustration shows birds from the Cretaceous Period, with dinosaurs in the background. A new study in the journal Science reveals the earliest-known evidence of birds nesting in polar regions. (Image: Illustration by Gabriel Ugueto)

Springtime in the Arctic feels like a wild nursery. Birds arrive by the millions to raise their young in the icy light. Now, scientists say this yearly tradition dates back far longer than anyone believed.

Earliest Polar Nesting Sites Uncovered in Alaska

A recent study, published in Science, shows birds were nesting in the Arctic 73 million years ago. This is the earliest evidence of bird breeding in polar regions. The discovery pushes the known record back by 25 million years.

Lead author Lauren Wilson, now a PhD student at Princeton, began this work during her master’s research at the University of Alaska Fairbanks. Using fossilised bones and teeth found near Alaska’s Colville River, she and her team identified multiple bird types. These included diving birds like loons, gull-like species, and birds similar to today’s ducks and geese.

The fossils were found in the Prince Creek Formation on Alaska’s North Slope. They came from sediment layers already known for dinosaur discoveries. Over 50 bird bones were recovered, some of them so small and delicate that finding them intact was a rare feat.

“These are baby bird bones,” Wilson explained. “They are very fragile and almost never survive.”

Birds Nested in the Arctic During Dinosaur Times

The fossils date to 73 million years ago, during the late Cretaceous period. That means these birds were raising their young while dinosaurs still roamed the same region.

Before this find, the earliest known example of birds nesting in polar regions was 47 million years ago. The new evidence predates the asteroid impact that wiped out most life on Earth.

“This means birds have been nesting in the Arctic for at least half of their history,” said Pat Druckenmiller, director of the University of Alaska Museum of the North and Wilson’s former advisor. He was the senior author on the study.

He added that Alaska now ranks as one of the top sites in North America for fossil bird discoveries from the age of dinosaurs.

Tiny Bones, Big Questions

The fossils offer more than just a new date. Some of the bones show features found only in Neornithes, the group that includes all modern birds. Some fossils even lacked true teeth, another sign of their modern lineage.

“If these are modern birds, they would be the oldest ever found,” Druckenmiller said. The current record for Neornithes fossils is about 69 million years old. Still, a full or partial skeleton would be needed to confirm that.

The discovery was possible thanks to a careful excavation method. Scientists collected not just big bones but also microscopic remains. Sediment was screened and carried back to the lab for close study.

This approach has helped uncover several new species and deeper insight into Arctic wildlife during the Cretaceous. The research highlights the value of preserving even the smallest remains.

Other contributors to the study include scientists from the Bruce Museum, Princeton University, University of Reading, Florida State University, Royal Tyrrell Museum, University of Colorado Boulder, and Montana State University.