Peafowl is a species of birds that include two Asiatic species (the blue or Indian peafowl originally of India and Sri Lanka and the green peafowl of Myanmar, Indochina, and Java) and one African species (the Congo peafowl native only to the Congo Basin) of bird in the genera Pavo and Afropavo of the Phasianidae family, the pheasants and their allies, known for the male's piercing call and, among the Asiatic species, his extravagant eye-spotted tail covert feathers which he displays as part of a courtship ritual. The term peacock is properly reserved for the male; the female is known as a peahen, and the immature offspring are sometimes called peachicks.
The functions of the elaborate iridescent coloration and large "train" of peacocks have been the subject of extensive scientific debate. Charles Darwin suggested they served to attract females, and the showy features of the males had evolved by sexual selection. More recently, Amotz Zahavi proposed in his handicap theory that these features acted as honest signals of the males' fitness, since less fit males would be disadvantaged by the difficulty of surviving with such large and conspicuous structures.(Wikipedia)