Birds are a family of animals that descended from the dinosaurs. They are found worldwide.
They are a clade of modern air-breathing, warm-blooded vertebrates. The ones that currently survive lack teeth, but possess a horny or bony beak, are covered in feathers and can fly. Yet birds are not related to pterosaurs or modern bats (mammals), and instead, they are dinosaurs - the only ones who had survived the K/T mass extinction.