Why are peacock feathers colored?

In 1634, Sir Theodore de Mayerne, physician to Charles I, observed that the 'eyes' on the wings of the peacock butterfly "shine curiously like stars, and do cast about them sparks of the colour of the Rainbow; by these marks is it so known that it would be needless to describe the rest of the body though painted with a variety of colours."

In general, the diversity of bird feathers colors can be explained by mere two factors: pigments on one side and simple structures in the feathers which interfere with the incident light. Pigment particles are embedded into the newly grown feathers during the molting season. They absorb light of certain wavelength or disperse the reflected light and thus contribute to the color of the plumage.

Each feather consists of thousands of flat branches. When like shines on the feather, we see thousands of glimmering colored spots, each caused by minuscule bowl-shaped indentations. Stronger magnification reveals microscopic lamellae (thin platelike layers) at the bottom of the indentations (see photo below). Just like in butterfly wings, the regular pattern of the lamellas leads to interference phenomena and thus to iridescent colors. This principle is also responsible for varied colors of pheasants, birds of paradise and humming birds.

View at different angles.The color of a peacock feather is caused by its complex structure. The coloring changes with the angle of incident light - a characteristic feature of the structure-caused colors due to microlamellas.
Is it really just interference?
Yes. For example, the white color of this white peacock is due to the missing black melanine pigment. The usual rich colors of the peacock are seen because black pigment which absorbs most of the incident light, allowing us to see only the interferece colors. In this peacock, the interference is still happening, but the effect is entirely washed out by the abundance of white light. In this peacock, you can see that the "eyes" of the tail feathers are clear, not colored.

Peacock Feather

Close-up of a peacock feather.

Peacock Information and Facts

Peacocks are native to India, but can live in many parts of the world in captivity. There are many different kinds of peacocks including the Indian Blue, Black Shouldered, Congo, Green, and White peacocks. White peacocks are the same as the Indian Blue in size and behavior, but are white.

In the wild, male Peacocks generally accumulate a harem of 2 - 5 females. However, in captivity, they are usually satisfied with one. The male has an extremely long train (commonly called his tail) which is NOT actually his tail. The train serves as a cover for the actual tail, which is brown. The train actually sprouts from the center of the back. Peacocks grow to 7' from tip of beak to end of train.


Males are called Peacocks and females are called Peahens. The collective term for both male and female is Peafowl. Peacocks need a great amount of companionship. If you are interested in purchasing one, you will want to get two unless you want a very unhappy bird. I have had peacocks fly away looking for their mates after the peahen dies. Peacocks love to be with one another and close to each other.

The main purpose of the male's train is to entrance the female to get her to mate with him. He spreads his train and displays an incredible fan of beautiful blues, greens, violets, reds, oranges and yellows. Every area of the train changes color when struck by different angles of light. The male vibrates his tail rapidly at the female in an attempt to impress her. He shakes his wings and turns from left to right. However, even with this awesome display, it is very rare that we ever see them mate. The female usually pretends not to notice the male. When she is ready to lay eggs, she will decide to mate with the male. Later, an egg fairly larger than a chicken egg is layed. After 28 days of incubation, the egg hatches. There is no fixed amount of eggs that the peahen will lay. She will also sometimes lay decoy eggs away from the nest to distract predators.

After the 28 (sometimes shorter) days of incubation, the chick hatches and looks somewhat disgusting. It is still covered with substances from the inside of the egg.

The egg left behind by the chick is quite gross-looking on the inside. There is a yellowish-brown membrane left behind called the alontoias membrane. This is material that the peachick's (as they are called) body has digested and does not need.

When the chick is not even one day old, it can walk, eat and drink on it's own. Baby peacocks are born with flight feathers already on their wings and can fly by the time they are one week old. They need to be able to do this to fly into trees at night.

White-Blue Peacock

Mixed between Blue and White Peacock.