Male birds-of-paradise living in the tropics have a super black plumage which is velvety as if made up of man-made materials. The lustrous feathers absorb light and reflect mesmerizing colors with the aim to attract females.
Findings by a team of researchers from the Harvard University, published in the journal Nature Communications exactly shows how the birds work wonders with light.
When light reflects on the surface of these birds' feathers or on tiny structures, the feathers get their colors. However, the black plumage of the birds-of-paradise is not exactly iridescent, according to co-author Dakota McCoy, an evolutionary biologist at Harvard University.
Findings from her team show that the male birds absorb up to 99.95 percent of the visible light. The tiny structures on their flight feathers have small hooks that form an aerodynamic surface. These structures are completely different from those found in butterflies or snakes. When light falls on these structures it tilts 30 degrees towards the outer tip and reflects into the cavities and not outwards.
Matthew Shawkey, an evolutionary biologist at Ghent University in Belgium, said that these recent findings actually reveal a new type of microstructure for feathers. The scales enhance the black color on the feathers that is produced by the feathers' pigments. The male birds reflect 10 to 100 times more light and its light-absorbing ability originates from the microstructures in the feathers.
During the research, the team observed that the super black feathers remained velvety even after a thin color was applied. Normal black feathers, however, appeared golden after the colour application.
McCoy and her team claim that the super black plumage has evolved primarily to attract the female while mating. The male birds portray their super black feathers in such a way while mating that they appear their darkest from the female's point of view, adds McCoy.
"This is definitely not about camouflage," said Shawkey. "This super black plumage is enhancing the contrast with those bright-coloured feathers nearby."
