In birds, the jaws are drawn out to form a horny beak which does not have teeth. Birds use their beaks for feeding. The beaks show adaptations according to the types of food the birds eat. In many birds, the feet also show adaptations for feeding.
The alimentary canal of the bird consists of the pharynx, oesophagus, crop , gizzard, intestine, anus and cloaca.
Birds swallow their food whole and store it in the crop. Here, it is softened by secretions from the walls of the crop. It then passes into the gizzard, a strong muscular bag. The action of the muscles of the gizzard and the gastric juice churn and break up the food into small pieces. Small stones (which the bird swallows from time to time) in the gizzard also helps to grind the food. chemical digestion also begins here. Digestion is completed in the small intestine by the action of the pancreatic juice and intestinal secretions. Absorption also takes place here. In the rectum, most of the water is reabsorbed. Solid waste is egested through the anus into the cloaca and out of the body. Body waste from the kidney, and eggs and sperms also leave the body through the cloaca.
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