Crows and blackbirds are black, but they aren't super black. In the light, their feathers reflect iridescent colors, often gray or blue, even though we always know they are black. Several species of birds of paradise have take black a lot more seriously. They absorb light, so that their bodies look like holes in the scenery. You can't see their contours at all. The secret is in the structure of their feathers.
A typical bird feather has a central shaft called a rachis. Thin branches, or barbs, sprout from the rachis, and even thinner branches—barbules—sprout from the barbs. The whole arrangement is flat, with the rachis, barbs, and barbules all lying on the same plane. The super-black feathers of birds of paradise, meanwhile, look very different. Their barbules, instead of lying flat, curve upward. And instead of being smooth cylinders, they are studded in minuscule spikes. “It’s hard to describe,” says McCoy. “It’s like a little bottle brush or a piece of coral.”
These unique structures excel at capturing light. When light hits a normal feather, it finds a series of horizontal surfaces, and can easily bounce off. But when light hits a super-black feather, it finds a tangled mess of mostly vertical surfaces. Instead of being reflected away, it bounces repeatedly between the barbules and their spikes. With each bounce, a little more of it gets absorbed. Light loses itself within the feathers.
The result is that a bird of paradise can absorb up to 99.95% of the light that hits its feathers, making the bird almost as black as Vantablack paint. Some butterflies and at least one snake have super-black light-absorbing abilities, too. But why does the bird of paradise need to be so dark? Read about these light-swallowing birds at the Atlantic. -via Damn Interesting
(Image credit: Flickr user Francesco Veronesi)