**Ancient Birds Nested in Arctic 73 Million Years Ago, New Fossils Reveal**

A groundbreaking discovery in the frozen expanse of northern Alaska has profoundly altered our understanding of ancient avian life. Fossil fragments suggest that birds were nesting in the Arctic a staggering 73 million years ago, a full 30 million years earlier than scientists previously believed.

The research, spearheaded by Lauren Wilson from Princeton University, involved painstaking excavation work in one of the Earth's coldest and most remote regions. More than 50 fossilized bone fragments were uncovered from the Prince Creek Formation, a site that lies approximately 1000 to 1600 kilometers closer to the North Pole than its current location. This area once formed a coastal floodplain, providing a unique snapshot into ancient ecosystems.

The expedition faced extreme conditions, with team members braving temperatures of -30 °C (-22 °F) and living in tents during their fieldwork. Back in their labs, the researchers meticulously sorted sediment grains smaller than two millimeters to identify bone pieces. These tiny fragments, exhibiting a sponge-like texture indicative of rapid growth, belonged to bird chicks or embryos.

The significance of this discovery cannot be overstated. It provides the earliest evidence of birds nesting in high Arctic latitudes during the Late Cretaceous period, an era dominated by dinosaurs like tyrannosaurs and ceratopsians. Notably absent from the fossil record were enantiornithines, a dominant bird group of that era found in other global records. Gerald Mayr from the Senckenberg Research Institute suggests that this absence implies evolutionary advantages among birds more closely related to modern species, allowing them to thrive in such extreme conditions.

Wilson’s team identified three main groups within the fossilized remains: extinct toothed birds akin to modern loons, extinct gull-like toothed birds, and some early representatives of modern bird lineages. Whether these ancient birds were year-round residents of the Arctic or seasonal breeders remains uncertain. However, what is clear is that they adapted to breed in high-latitude environments far earlier than previously thought.

As Steve Brusatte from the University of Edinburgh notes, this discovery underscores how integral birds have been to Arctic ecosystems for tens of millions of years. Whether migrating or enduring the harsh winters, birds remain a vital part of these high-latitude environments today, continuing a legacy that extends deep into prehistoric times.