Fossils from 73 Million Years Ago Reveal the Earliest Evidence of Bird Nesting in Polar Regions

Polar ecosystems are bolstered and enriched by birds that nest there seasonally, serving as keystone members of these ecosystems. Despite the significant ecological role of polar birds, the origins of high-center nests remain unclear due to limited fossil evidence. A recent study conducted by paleontologists explored an extensive collection of bird fossils from the late Cretaceous Purine Cream Formation in Alaska.

“Birds have existed for 150 million years,” stated Lauren Wilson, a doctoral candidate at Princeton University.

“For a significant portion of that time, they constructed nests in the Arctic.”

In their research, Wilson and colleagues studied the bones and teeth of fossilized birds from the Alaska Prune Creek Formation, dating back 73 million years.

They identified various bird types, including land birds, seagull-like birds, and diving birds that bear similarities to some modern ducks and geese, all of which were nesting in the Arctic while dinosaurs roamed the same territory.

Before this research, the earliest known evidence of breeding birds in the Arctic or Antarctic was approximately 47 million years ago, following the asteroid impact that wiped out 75% of Earth’s species.

“This will extend the timeline by 25-30 million years for records of birds breeding in the polar regions,” remarked Dr. Pat Druckenmiller, director of the University of Alaska Museum.

“The Arctic is recognized as a modern nursery for birds.”

“Finding bird bones from the Cretaceous period is exceptionally rare,” Wilson noted.

“Discovering baby bird bones is almost unheard of, making these fossils particularly significant.”

“We conducted extensive mapping of Alaska for fossil birds—it wasn’t on anyone’s radar,” added Dr. Druckenmiller.

“Now, we are one of the premier locations in the country for bird fossils from the dinosaur age.”

“Given the richness of this information, these small bones and teeth offer exceptional insights into the fauna from that era.”

It remains uncertain whether these newly discovered specimens are the earliest recognized members of Neornithes, a category that encompasses all modern birds.

Some of the newly unearthed bones exhibit skeletal characteristics exclusive to this group. Additionally, like contemporary birds, some did not possess true teeth.

“If they belong to a modern bird lineage, they would represent the oldest fossils ever found,” explained Dr. Druckenmiller.

“Currently, the oldest such fossils are about 69 million years old.”

“However, establishing that requires the discovery of a partial or complete skeleton.”

Survey results I will be featured this week in the journal Science.

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Lauren N. Wilson et al. 2025. Evidence of bird nesting in the Arctic dates back to the Cretaceous period. Science 388 (6750): 974-978; doi: 10.1126/science.adt5189