Peacock

The male (peacock) Indian Peafowl has iridescent blue-green or green coloured plumage. The peacock tail ("train") is not the tail quill feathers but the highly elongated upper tail coverts. The "eyes" are best seen when the peacock fans its tail. Like a cupped hand behind the ear the erect tail-fan of the male helps direct sound to the ears. Both species have a crest atop the head. The female (peahen) Indian Peafowl has a mixture of dull green, brown, and grey in her plumage. She lacks the long upper tail coverts of the male but has a crest. The female can also display 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 green and gold plumage and has 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. It is difficult to tell a juvenile male from an adult female.

As with many birds, vibrant plumage colours are not primarily pigments, but optical interference Bragg reflections, based on regular, periodic nanostructures of the barbules (fiber-like components) of the feathers. 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 interference-based structural colour is important for the peacock's iridescent hues that change and shimmer with viewing angle, since unlike pigments, interference effects depend on light angle.