Sub phylum- Vertebrata
Type- Columba livia
Birds are easily recongnised group of vertebrates. In birds every part of the body is modified to suit their aerial mode of life. Birds possess feathers, beak and feet modified in relation to their aerial life.
The Pigeons are flying birds (carinate). They are known both as wild and domesticated forms. The Pigeons are seen both in tropical and temperate zones. About 10 species of Pigeons are found in India. The pigeons fly in flocks and roost together. The domestic pigeons have many varieties, namely panter, fantail and tumblers. They differ in size, colouration and feather ar-rangement. All of them are, however, descendants of the rock pigeon-columba Livia.
Fig: Pigeon – External
The Body is spindle shaped. Their size varies from 20-25 cm. They are covered by coloured feathers leaving beak and a small portion of the hindlimbs.
The body is divisible into head, neck, trunk and a small, conical tail. The head is round and drawn out anteriorly into a strong, hard, pointed beak. The mouth is a terminal wide gape, guarded by elongated upper and lower beaks. The beaks are covered with a horny sheath or rhampotheca. A swol-len area of soft skin, the cere, surrounds the nostril. It is present on each side of the upper beak. The eyes are large and guarded by upper and lower eye-lids and a transparent nictitating membrane. A pair of ear openings are situated at a short distance behind the eyes. Each opening leads into a short external auditory meatus, ending in the tympanic membrane forming the ear drum.
The neck is long and mobile. It helps in the movement of the head in various directions. The trunk is compact, heavy and bears a pair of wings and a pair of legs. The cloacal aperture is at its hind end on the lower surface. Projecting behind the cloacal aperture is the tail. Above the tail is a knob on which opens an oil gland or preen gland or uropygeal gland. It secretes a fluid used for preening the feathers.