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Scientists Shine New Light on the Blackest Black Feathers

Birds of paradise feathers boast a unique structure that traps 99.95 percent of incoming light

smithsonian.com

Plenty of birds have black feathers: crows, ravens, cormorants, the aptly named blackbird. But when it comes to stunningly dark plumage, none of them compare to birds of paradise, a group of 39 species that primarily dwells in Papua New Guinea. These beautiful creatures boast bright, electric colors juxtaposed by feathers so black that they can rival the blackest materials designed by humans, Ed Yong reports for the Atlantic.

To get a sense of the deep blackness of the birds’ feathers, look no further than the above clip from BBC Earth, which shows a male superb bird of paradise engaging in a mating ritual. He puffs his feathers out into a halo, and with the exception of three brilliant swaths of blue, all of his features disappear into a void of blackness.

A team of researchers recently took a closer look at bird of paradise feathers, in the hopes of learning more about their incredible opacity. The study’s findings, published this week in the journal Nature Communications, revealed that certain bird of paradise feathers boast a unique, light-trapping structure.  As Yong explains, the feathers of most other birds have a central shaft, or “rachis,” which splinters off into branches known as “barbs,” and then into thinner branches called “barbules.” The structure is flat and relatively orderly. Some bird of paradise feathers, on the other hand, are irregular, with curved, spiky barbules and cavities within the feathers.

This arrangement is exceptionally good at absorbing light. “Light strikes the feather, and is repeatedly scattered within these cavities,” Dakota McCoy, a Harvard evolutionary biologist and lead author of the study, tells Matt Simon of Wired. “Each time it scatters, a little bit is absorbed, so that's how they become so black.” 

McCoy and her fellow researchers found that paradise feathers can capture up to 99.95 percent of incoming, head-on light. (That number was reduced slightly, to 96.86 percent, when light was shone on the feathers from all sides). The feathers are so dark, in fact, that they trap nearly as much light as Vantablack, a super-black substance invented by British researchers in 2014. Vantablack is said to be the world’s darkest man-made substance; it absorbs 99.965 percent of incoming light.

Super-black bird of paradise feathers trap between 10 and 100 times more than the black feathers of other birds, according to Yong. To illustrate this discrepancy, researchers sprinkled gold dust onto two feathers: one belonging to the lesser melampitta, a type of songbird, and the other to a bird of paradise species. Photos from the experiment show that after the dusting, the lesser melampitta feather looked shiny and gold. But the bird of paradise feather still showed up blacker than the night sky.

Why do these creatures boast such dark plumage? Researchers theorize that the birds’ super-black feathers make their colorful plumage appear even more brilliant, which makes them more attractive to females. Indeed, the microstructures of feathers not involved in bird of paradise mating displays do not have the same characteristics of the super-black plumage.

“Sexual selection has produced some of the most remarkable traits in nature,” Rick Prum, a professor of ornithology and evolutionary biology at Yale and a senior author of the study, observes in a Yale press release.

Who needs a wing man when supremely cool feathers will do?

About Brigit Katz

Brigit Katz is a freelance writer based in Toronto. Her work has appeared in a number of publications, including NYmag.com, Flavorwire and Tina Brown Media's Women in the World.

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