Bird - Wikipedia Birds are a group of warm-blooded theropod dinosaurs constituting the class Aves, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton
Bird - Aves, Species, Orders | Britannica Bird - Aves, Species, Orders: In classifying birds, most systematists have historically relied upon structural characteristics to infer evolutionary relationships
Class Aves - Classification, Examples, its Characteristics The aves class contains around 9000 species that show courtship, parental care, nest building, and most importantly territorial behavior Aves are the first vertebrates who have warm blood in their body
Aves (birds) | INFORMATION | Animal Diversity Web - ADW Birds are vertebrates with feathers, modified for flight and for active metabolism Birds are a monophyletic lineage, evolved once from a common ancestor, and all birds are related through that common origin There are a few kinds of birds that don't fly, but their ancestors did, and these birds have secondarily lost the ability to fly