Indian Peafowl: Where Beauty Is More Than Skin Deep

The Peafowl includes two Asiatic species, Pavo muticus and Pavo cristatus, originally of India, Sri Lanka and the tropical forests of Southeast Asia, specifically Myanmar, Indochina and Java and one African species, Afropavo congensis, native of only Congo. Of the family Phasianidae, the pheasants are known for the male’s periling call and extravagant eye-spotted tail covert feathers displayed as part of a courtship ritual. People tend to recognize a peacock easily, but the peahen confuses some. To break this down, a peacock is a male and the peahen is a female. Together they are called peafowl. Peacocks have all the magnificent feathers. All of them. Peahens? Not so much. Females are much smaller in size and duller in color. Males don the colorful, distinctive feather that attract the peahens. Females are a freckled brown color with a greenish neck and head, lacking the adored long tail. Believe it or not, peafowls come in a variety of colors.

Plumage

The Indian peacock has a magnificent blue and green plumage, growing up to 6ft and making up 60% of its body length. Despite their odd proportionality, peacocks are the largest flying birds. The peacock “tail”, known as a “train”, consists not of tail quill feathers, but highly elongated upper tail coverts.

chicken_wing
Covert Feather

A covert feather on a bird is one set of feathers, which as the name implies, covers the feathers. They assists in smooth airflow over the wings and tail. These feathers are distinct with eyespots, best detected when a peacock fans his tail. Both sexes bear a crest atop their head. The Indian peahen has a combination of dull grey, brown and green in her plumage. The female will also exhibit her plumage to fend off female competition or signal danger to her young.

Chicks, or peachicks, are vaguely colored. They vary between yellow and tawny, usually with patches of darker brown or light tan and ivory.

Iridescence

As with many birds, lively iridescent plumage coloration are not pigments, for the most part, but structural coloration, a production of color by microscopic crystal-like structured surfaces fine enough to interfere with visible light, sometimes in combination with pigments. Regular, periodic nanostructure of barbules of the feathers produce the peacock’s colors. The crystal-like structures that reflect different wavelengths of light are dependent on the spacing of the barbules resulting in the different bright flourescent colors. Brown feathers are a combination of red and blue. Structural coloration causes the iridescence of the peacock’s chroma. Iridescence depends on the light angle rather than actual pigments.

 

Sexual Selection

Courtship

Charles Darwin first theorizes in On the Origin of Species that the peafowl’s plumage evolves through sexual selection, the ability of male and female organisms to make use of selective forces on each other with regard to mating activity. The peahen’s reproductive success and likelihood for survival of the chicks is partially dependent on the genotype of the mate. Female have more to lose when mating with an inferior male due to her  gametes being more costly than the male’s.

Female choice

Some hypotheses have been made in efforts to explain the evolution of female choice. Many suggests direct benefits to females, such as protection, shelter, or conjugal gifts to influence a female’s choice. Other hypotheses suggests female choice is based on good genes. Males with more extravagant secondary sexual characteristics, such as bigger, luminous trains tend to have better genes in the peahen’s perspective. These genes will directly benefit the peahen’s offspring, as well as the fitness and reproductive success. Females have often shown to distinguish among potential mates, and to prefer mating with individuals bearing the most exaggerated characters. In some cases, those males have shown to produce more successful, healthy and vigorous males.

Plumage colors as attractants

Copulation success rate of the peacock depends on the colors of his eyespots, or ocelli, and the angle at which they are displayed. At courtship, the angle the ocelli are displayed are influential in a peahen’s choice of males than train size or number of ocelli. During a peacock’s performance, peahens pay close attention to the various parts of the peacock’s train. The lower train is evaluated during close-up courtship, while the upper train is responsible for long distance attraction. Actions such as train rattling and wing fluttering also keep a peahens’ attention.

Diet

Peafowls are omnivores and eat mostly plant parts, actively hunting insects and other arthropods, reptiles and amphibians. Scratching through leaf litter is how wild peafowls find their food. They’re not picky and will eat almost anything that can fit into their beak.

Conservation

The IUCN Red List categorizes Indian Peafowl as “least concern”. Their population is hypothesized to be adamant and under control and believed to be abundant in living environments.

 

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Indian Peafowl at Brookfield Zoo

Resources:

Jobson, Christopher. “The Extraordinary Iridescent Details of Peacock Feathers Captured Under a Microscope.” Colossal. Colossal, 30 Mar. 2016. Web. 30 Nov. 2016.

@NatGeo. “Peacocks | National Geographic.” National Geographic. National Geographic Partners, 28 Nov. 2016. Web. 30 Nov. 2016.

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