Bird Bird Bird Bird
Bird Bird Bird Bird
 Bird Bird Bird Bird
Bird Bird Bird Bird


The birds have been descended from their immediate ancestors, the reptiles.
Scientists believe that the earliest known bird that lived over 140 million years age is Archaeopteryx. Like mammals, birds are warm blooded animals i.e. they can maintain their body temperatures more or less constant and independent of surrounding atmosphere. The main characteristic feature of birds is their feathers. They grow from the epidermis and are made of keratins. They do not have sweat glands. The oil gland (preen gland) is located on the rump at the base of the tail and it keeps plumage waterproof. Normally, feet are covered with scales. The toes are tipped with claws. Typically the first toe directed backwards and the second, third and fourth toes are directed Birds play vital roles in maintaining the ecological balance as well as welfare of the human being. Wild birds and eggs are the food sources of human being. Feathers have been used for decoration since early times. Pigeons have been trained for carrying a message. Birds help in cross pollination in flowers. They also play an important role in controlling of pests and dispersal of seeds as well. The droppings of fish eating water birds are valued for fertilizer.in front. The fifth toe is absent. The upper mandible which is attached to the skull is movable to some extent. The heart is four chambered. The aortic artery is lost. Living birds have no teeth. Birds have highly sight and hearing. Some members are solitary (e.g. many birds of prey) while others are gregarious (e.g. flamingo). The nests are built by many birds for laying purpose. Eggs are incubated either by female alone or by both sexes (except in megapodes where eggs are hatched by heat generated by decaying vegetation). The incubation period varies from 11 to 80 days depending on the species. Most species have nearly naked and helpless young (altrical). The life span varies according to a particular group of birds. An ostrich, for example, can live for more than 40 years, while perching birds usually have a life span of 5 to 8 years.
Birds play vital roles in maintaining the ecological balance as well as welfare of the human being. Wild birds and eggs are the food sources of human being. Feathers have been used for decoration since early times. Pigeons have been trained for carrying a message. Birds help in cross pollination in flowers. They also play an important role in controlling of pests and dispersal of seeds as well. The droppings of fish eating water birds are valued for fertilizer.