The category that includes birds and reptiles is called Archosauria. This clade is part of the larger group of reptiles and consists of two main branches: the avialans (birds) and the non-avialan archosaurs (which include crocodilians and their extinct relatives such as dinosaurs). Archosaurs are characterized by specific features, such as a larger size in many species and distinctive ankle structures. This group provides an interesting insight into evolutionary biology, showcasing how birds are modern descendants of theropod dinosaurs, linking them to their ancient relatives. Archosauria plays a crucial role in understanding reptilian evolution.