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Info from wikipedia
Peafowl are two Asiatic and one African species of flying bird in the genus Pavo of the pheasant family, Phasianidae, best known for the male's extravagant eye-spotted tail covert feathers, which it displays as part of courtship. The male is called apeacock, the female a peahen, and the offspring peachicks.[1] The adult female peafowl is grey and/or brown. Peachicks can be between yellow and a tawny colour with darker brown patches or light tan and ivory, also referred to as "dirty white". The term also includes the Congo peafowl, which is placed in a separate genusAfropavo.
In common with other members of the Galliformes, males possess metatarsal spurs or "thorns" used primarily during intraspecific fights.
White peacocks are not albinos; they have a genetic mutation that is known asleucism, which causes the lack of pigments in the plumage. Albino mammals and birds have a complete lack of color and red or pink eyes while White peafowl have blue eyes. The white color appears in other domestically bred peafowl but in different quantities. Chicks are born yellow and become white as they mature.[2] Indian peafowl of all colors, including white, have pink skin.
The species are:
- Congo peafowl Afropavo congensis.
- Green peafowl, Pavo muticus. Breeds from Burma east to Java. The IUCN lists the green peafowl as endangered due to hunting and a reduction in extent and quality of habitat. It is a national symbol in the history of Burma.
- Indian peafowl, Pavo cristatus, a resident breeder in South Asia. The peacock is designated as the national bird of India.
Plumage[edit]
The male Indian peafowl (peacock) has iridescent blue or green-colored plumage. The peacock tail ("train") is not the tail quill feathers but the highly elongated upper tail covert feathers. The "eyes" are best seen when the peacock fans its tail. Both species have a crest atop the head. The female Indian peafowl (peahen) has a mixture of dull grey, brown, and green in her plumage. Although she lacks the long upper tail coverts of the male, she has a crest. The female also displays her plumage to ward off female competition or signal danger to her young.
The green peafowl appears different from the Indian peafowl. The male has a green and gold plumage as well as an erect crest. The wings are black with a sheen of blue. Unlike the Indian peafowl, the green peahen is similar to the male, only having shorter upper tail coverts and less iridescence.
Colouration[edit]
As with many birds, vibrant iridescent plumage colours are not primarily pigments, butstructural colouration. Optical interference Bragg reflections, based on regular, periodic nanostructures of the barbules (fiber-like components) of the feathers produce the peacock's colors. Slight changes to the spacing result in different colours. Brown feathers are a mixture of red and blue: one colour is created by the periodic structure, and the other is a created by a Fabry–Pérot interference peak from reflections from the outer and inner boundaries. Such structural colouration causes the iridescence of the peacock's hues since, unlike pigments, interference effects depend on light angle.
Colour mutations exist through selective breeding, such as the white peafowl and the black-shouldered peafowl.
Evolution and sexual selection[edit]
Charles Darwin first theorized in On the Origin of Species that the peacock's plumage had evolved through sexual selection. This idea was expanded upon in his second book, The Descent of Man and Selection in Relation to Sex.
Work concerning female behavior in many species of animals has sought to confirm Darwin's basic idea of female preference for males with certain characteristics as a major force in the evolution of species.[4]Females have often been shown to distinguish small differences among potential mates and to prefer mating with individuals bearing the most exaggerated characters.[5] In some cases, those males have been shown to be more healthy and vigorous, suggesting that the ornaments serve as markers indicating the males' abilities to survive and, thus, their genetic qualities.
Females lost interest in pruned males and became attracted to untrimmed ones. Further testing revealed that males with fewer eyespots, and thus with lower mating success, were more likely to suffer from greater predation.[8] Even more interestingly, she allowed females to mate with males that had variable numbers of eyespots and reared the offspring in a communal incubator to control for differences in maternal care. Chicks fathered by more ornamented males weighed more than those fathered by less ornamented males, an attribute generally associated with better survival rate in birds. When these chicks were released into the park and recaptured one year later, those with heavily ornamented fathers were found to be better able to avoid predators and survive in natural conditions.[4] Thus, Petrie's work has shown correlations between tail ornamentation, mating success and increased survival ability in both the ornamented males and their offspring.
Furthermore, peafowl and their sexual characteristics have been used in the discussion of the causes for sexual traits. Amotz Zahavi used the excessive tail plumes of male peafowls as evidence for his “Handicap Principle”.[9] Considering that these trains are obviously deleterious to the survival of an individual (due to the more brilliant plumes being highly visible to predators and the longer plumes making escape from danger more difficult), Zahavi argued that only the most fit males could survive the handicap of a large tail. Thus, the brilliant tail of the peacock serves as an indicator for females that highly ornamented males are good at surviving for other reasons, and are, therefore, more preferable mates. This theory may be contrasted with Fisher's theory that male sexual traits, such as the peacock's train, are the result of selection for attractive traits because these traits are considered attractive.
However, some disagreement has arisen in recent years concerning whether or not female peafowl do indeed select males with more ornamented trains. In contrast to Petrie's findings, a seven-year Japanese study of free-ranging peafowl came to the conclusion that female peafowl do not select mates solely on the basis of their trains. Mariko Takahashi found no evidence that peahens expressed any preference for peacocks with more elaborate trains (such as trains having moreocelli), a more symmetrical arrangement, or a greater length.[10] Takahashi determined that the peacock's train was not the universal target of female mate choice, showed little variance across male populations, and, based on physiological data collected from this group of peafowl, do not correlate to male physical conditions. Adeline Loyau and her colleagues responded to Takahashi's study by voicing concern that alternative explanations for these results had been overlooked, and that these might be essential for the understanding of the complexity of mate choice.[11] They concluded that female choice might indeed vary in different ecological conditions.
It has been also suggested that peacocks' display of colorful and oversize trains with plenty of eyespots, together with their extremely loud call and fearless behavior, have been formed by the forces of natural selection (not sexual selection), and served as an aposematic warning display to intimidate predators and rivals. [12]
Peafowl are forest birds that nest on the ground but roost in trees. They are terrestrial feeders. All species of peafowl are believed to bepolygamous. However, it has been suggested that peahens entering a green peacock's territory are really his own juvenile or sub-adult young and that green peafowl are really monogamous in the wild.[citation needed]
Diet[edit]
Peafowl are omnivorous and eat most plant parts, flower petals, seed heads, insects and other arthropods, reptiles, andamphibians.
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