what is 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, using powerful muscles to flap their wings, but not all birds can fly. They have wings, lay eggs, build nests, and have specialized beaks and feet. Feathers are a defining feature of birds, helping to keep them warm and dry, and enabling flight. Birds have a unique digestive system that allows them to eat when they can and digest later. They use their beaks to grab and swallow food. Birds are found worldwide and in all habitats, and they are adapted for various forms of locomotion, including flight, running, jumping, swimming, and diving