A multi-university team found that modern birds were nesting in the Arctic during the Cretaceous period, some 73 million years ago. “Prior to our research, the earliest known nesting of birds in that region was about 46 million years ago,” says FSU’s Gregory Erickson. “Birds are really important in the Arctic today…We were stunned to date their involvement back to the Age of Dinosaurs.”

Erickson and collaborators have been excavating an area on Alaska’s North Slope called the Prince Creek Formation for years. The area is rich with dinosaur fossils, but this time, the team also found bird fossils. Even rarer, some of the fossils turned out to be those of baby birds. Erickson confirmed via analysis of their microstructure that some were late-term embryos or hatchlings.

• Gregory Erickson