Birds are called members of the class Aves primarily due to their unique set of characteristics that distinguish them from other animals. The name ‘Aves’ is derived from the Latin word for bird.
One of the defining features of birds is their feathers, which are not found in any other group of animals. Feathers play a crucial role in insulation, waterproofing, and, most notably, flight. In addition to feathers, birds have a beak or bill instead of teeth, light bones that help reduce body weight for flying, and a high metabolic rate to support their active lifestyles.
Moreover, birds lay hard-shelled eggs, which is another characteristic that aligns with the properties of Aves. Their unique respiratory system, which includes air sacs, enables efficient oxygen exchange and supports their high energy needs while flying. All these traits combined shape the distinct identity of birds as members of the class Aves.