what a bird

A bird is a warm-blooded vertebrate that belongs to the class Aves. It is characterized 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. Most birds can fly, which distinguishes them from almost all other vertebrate classes. They have various adaptations for flight, including a lightweight skeleton and two large flight muscles. Feathers, wings, and the ability to lay eggs are some of the key features that define a bird