Birds Nested in Arctic 73 Million Years Ago

Recent discoveries of more than 50 fossilized bird bones, including embryos and hatchlings, from the Late Cretaceous Prince Creek Formation in northern Alaska provide the earliest evidence of birds nesting in Arctic regions, dating back about 73 million years. These fossils reveal that some early ancestors of modern birds, including ornithurines like Ichthyornithes, adapted to or migrated through harsh polar conditions, significantly pushing back the known timeline of avian polar nesting by 25 to 30 million years. This challenges previous assumptions that primitive birds could not survive Arctic winters or undertake long migrations at such an early evolutionary stage. The evidence highlights that birds have been integral to polar ecosystems since the Mesozoic era, coexisting with dinosaurs and playing critical ecological roles similar to modern Arctic bird species. Researchers emphasize that this ancient nesting behavior offers valuable insights into the evolutionary history of birds and the functioning of polar ecosystems over millions of years. The findings, based on painstaking fieldwork and microscopic fossil analysis, fill a major gap in understanding how birds came to thrive in extreme environments.