Colour Codes: Understanding Bird Colours

All of us love colourful birds. The more the colours the more of joy comes to our hearts after looking at those birds. Many of us may not know that how different birds acquire different colours and always wish to see the more brighter and colourful bird rather than just an ordinary mynah. Well, the answer lies in science and as well as survival.

Bird Colours are a result of the pigments flowing through them and the light which reflects off their feathers.

When light passes through a prism, that white light is divided into seven colours: Violet, Indigo, Blue, Green, Yellow, Orange and Red. When the light deflects, Violet has the shortest wavelength and red has the longest which makes the colour red look more prominent while violet is less visible. The same way when light passes through the feather of birds at a certain angle, they give out different colours. This means that Parrots, Bee-Eaters and barbets are not actually green, we see the light reflecting from their brown and slightly transparent feathers. The best example to prove this comes through the bird, "Anna's Hummingbird". This bird is mostly green and grey with wonderful feathers on its head which changes colour according to the angle of light. In low light this bird usually looks dull grey or brownish, but with the swing of its head, sometimes it may seem pink, or bright red and sometimes it changes to a rufous and orange colour. Hence, its the angle and not the colour of the feathers which determine what we see. Thankfully, raptors and many animals which prey on birds don't see their colours as bright as our eyes do, which helps these colourful birds to hide from them easily.

Anna' Hummingbird from California,USA

Anna's Hummingbird changing colours due to light angles.

Many birds also acquire their colour through eating certain food substances which release pigments in their body causing a change of colours. The best example for acquiring colour change are flamingoes.

Flamingoes are born dull brown or grey and they acquire their pink colour because a natural pink dye called "Canthaxanthin" which they obtain through eating brown shrimp or blue green algae.

American Falmingoes from Florida,USA acquire their colour from Canthaxanthin.

There are three main pigments which give feathers their colours.

The first pigment is called "Melanin". Melanin produces a dark and black colouration and it is also the pigment which makes the hair of mammals look black. Melanin is a very strong and rigid pigment and is mostly used up in the flight feathers of birds.

Grey Bushchat from HP, India contains mostly melanin in feathers.

The second group of pigments are called "Carotenoids" which produces colours such as Red, Yellow and Orange. Cartenoids are ingested through the food and fruits the bird eats.

The third group of pigments is called "Porphyrins" gives out colours such as Red, Pink ans Green. It is the rarest of all pigments and is possessed only by a few bird families.

A mixture of different pigments produces different colours and hues in a bird.

Sun Conure from Brazil contains a mix of carotenoids and porphyrins.

Keratin also plays a role in bird colouration as it's the feathers, bill and feet are made of this substance. Keratin is the same protein which helps in the formation of nail and horns in mammals. It produces colour through the process of layering and scattering.

Layering colours are produced when translucent keratin reflects short wave-lengths of colours like blues, violets, purples and greens.

Scattering is produced when the keratin of feathers is interspersed with tiny air pockets within the structure of the feathers themselves. These air pockets and the interspersed keratin scatter blue and green light and produce the shimmering colours of birds like kingfishers, rollers and bee-eaters.

Indian Roller from Haryana,India consists of scattering of Keratin.

Hence, the different colours of birds are a perfect combination of pigments and light angles.

Another aspect of colour change in most birds is that, the male bird is more brightly coloured than females.The theory of Charles Darwin concluded that colour differences between sexes in birds (also known as sexual dichromatism) result largely from female preference for bright colours in males. This general rule has received much support since Darwin's time, but other influences have also been noted. For example, females of species that are exposed to predators while incubating tend to have dull colours, although both sexes may be brightly coloured in species that nest in tree hollows because the females are less visible to predators. Colour can also aid individuals in recognizing members of their own species and in species that are not good to eat, colours can provide a warning to potential predators. Males also have bright colours and beautiful extensions of feathers through which they show their pomp and secure their territory.

All of these factors perfectly combine to support the structure of bird colourations which made me realise that colours are not meant only for beauty or for us to look at them, they are also meant for the survival and lifestyle of the birds and animals we see everyday.

Wilson's Bird of paradise from West Pappua New Guinea
The striking male is below the dull and brownish female.

The Call Of Colours

Indian Pitta at Mirzapur

Pittas are one of the most colourful birds in the world. The behaviour, the colour and the ecology is very elusive and attractive. It is a delight to all birders and ornithologists.
Pittas are colourful, long legged passerine birds as big as a myna but plumper and short tailed. They generally hop around the forest floors over fallen logs and dense undergrowth, usually roaming in loose pairs. They feed on insects, grubs, snails, worms, etc. They are quite shy and are best located by their characteristic whistling calls. Most likely seen at dawn or dusk, roosting on trees with their melodious call.
One of my favourite Pittas is the infamous Indian Pitta, which is a bird of nine colours. I have seen it quite a number of times now and observing it and listening to its call is always a delight no matter how many times I see it. The Indian Pitta resides in the south in winters and comes upto north India in summers for breeding. It generally nest and breeds in the Shivalik Foothills and Western Himalayas, and while its conquest to reach there, it can bee seen through various states of India. This year I  saw six of them at farm in Ropar, Punjab. The Indian Pitta starts calling at 6:00am in the morning and at 6:00pm during the evening, thus it is also called the six o clock bird. It mostly prefers scrub jungles or dense deciduous forests. Pittas also have a very keen sense of smell. Indian Pittas were found to have the largest olfactory bulb out of all passerine birds. Pittas are also quite clever birds and have been seen several times, using stones to crack open snail shells and eat them.

Malayan Banded Pitta I saw in Thailand

There are 42 species of Pittas found in Asia,          Australia and Africa and are divided in three  different genus: Hydrornis, Erythropitta and Pitta. Pittas are a very popular bird group amongst birders due to their dazzling plumages and the relative difficulty of seeing these birds hiding in dark, dense forests. The desire of birders to watch this bird is incredibly described in the book: "The Jewel Hunter" in which the writer Chris Goodie attempts to see every species of this bird.

Due to the amazing appearance of this bird, many bird and wildlife photographers go beyond the limit of ethical bird photography. They use huge flashes to get good photos of this bird as it is usually seen in darker forest areas and the flash causes temporary blindness to the bird and stuns it. In order to see it people usually play their recorded call which in return makes the Pitta respond, but can also

confuse it. However, I stand guilty of attempting to call the pitta by using a fake call, I do not use it now and don't recommend it to anyone else as it confuses the bird in thinking that the fake call is its partner.

The Blue Pitta I saw in Thailand.

Pittas are continuously facing a threat to endangerment due to forest and habitat loss. The Gurneys Pitta in Burma and the Blue Headed Pitta from Borneo are threatened by rapid forest loss. Pittas are targeted by poachers for illegal wild bird trade. I myself saw several Banded Pittas caged in a local bazaar in Bangkok, Thailand.They are not targeted because of their song, as many songbirds are, and may simply be captured as bycatch from collecting other species, and because of their attractive plumage.

 The attempts to breed these birds in captivity is not a total success as they are strongly territorial and can cover territories from 3000m square to 10000m square. In captivity they also get highly aggressive, attacking other bird species and even their own while this behaviour is not observed in the wild.
Being the most colourful birds on our planet one can never see enough of pittas and their beauty never ceases to surprise me and it is our duty to conserve our forests, so that the home of these beautiful bird remains preserved and let them bewilder us by their beauty.

Indian Pitta Calling