Mass extinction of birds at the Cretaceous-Paleogene (K-Pg) boundary.

Abstract in brief

• The study provides evidence that many archaic bird species persisted until close to the KPg mass extinction event, contradicting the idea that they went extinct gradually earlier in the Cretaceous.
• A diverse avifauna from the latest Maastrichtian period in North America includes 17 species, featuring archaic groups like Enantiornithes, Ichthyornithes, and Hesperornithes, all of which did not survive past the Cretaceous.
• The findings show that avian diversity and evolution significantly advanced before the mass extinction, including both small and large flying birds, indicating substantial diversification by the end of the Cretaceous period.