What is a bird? An evolutionary perspective on the first birds

"What is a bird? An evolutionary perspective on the first 'birds'" By Ezekiel O’Callahan. Birds are the most species-rich clade of any vertebrate on land, and this speaks to their success as the last dinosaurs on Earth. But at what point does a dinosaur stop being a dinosaur and start being a bird? Does it ever stop being a dinosaur? And why did they survive when the other dinosaurs died out? Come hear Zeke speak about the beginning of birds. Sponsored by Northern Arizona Audubon Society. 12:30 social time. Start time 1:00.