Why did birds survive the dinosaur extinction?

Around 66 million years ago, the Cretaceous-Paleogene extinction event wiped out three-quarters of Earth's plant and animal species, including all non-avian dinosaurs. However, a surviving lineage of feathered theropod dinosaurs, known as avian dinosaurs or modern birds, managed to endure through this global catastrophe. Their descendants subsequently diversified into all modern bird species during the Cenozoic era.

What we know

• The Cretaceous-Paleogene extinction event occurred approximately 66 million years ago and eliminated three-quarters of all plant and animal species on Earth. [2]
• All non-avian dinosaurs and pterosaurs were killed in the mass extinction, while the surviving dinosaur lineage consisted of avians, specifically ground and water fowl. [2, 5]
• Birds evolved from earlier theropod dinosaurs during the Late Jurassic epoch, making them the only living dinosaurs today. [4, 5]
• Following the extinction event, surviving bird groups underwent a massive adaptive radiation, leading to the evolution of thousands of modern species. [2, 5]

Where to go next

• what caused itWhat caused the Cretaceous-Paleogene extinction?
• what followedHow did mammals diversify after the dinosaur extinction?
• how it workedHow did feathered theropods evolve into modern birds?
• how we knowWhat evidence marks the boundary of the dinosaur extinction?
• the bigger pictureWhat are the general characteristics of the class Aves?
• an unexpected connectionHow are modern crocodiles related to birds?Although birds are classified as living dinosaurs, their closest surviving biological relatives outside of dinosaurs are actually crocodilians, with whom they share a common archosaur ancestor.

Sources

• [1]Cretaceous-Paleogene mass extinction (Wikidata Q55811) · CC0 1.0
• [2]Cretaceous–Paleogene extinction event · CC BY-SA 4.0
• [3]Holocene extinction · CC BY-SA 4.0
• [4]Dinosaur · CC BY-SA 4.0
• [5]Bird · CC BY-SA 4.0