Bird Feathers Produce Color Through Structure Similar to Beer Foam

Apr 02, 2009
Prum and Dufresne discovered that the nanostructures that produce some birds’ brightly colored plumage, such as the blue feathers of the male Eastern Bluebird, have a sponge-like structure. (Photo: Ken Thomas)

(PhysOrg.com) -- Some of the brightest colors in nature are created by tiny nanostructures with a structure similar to beer foam or a sponge, according to Yale University researchers.

Most colors in nature—from the color of our skin to the green of trees—are produced by . But the bright blue feathers found in many birds, such as Bluebirds and Blue Jays, are instead produced by . Under an , these structures look like sponges with air bubbles.

Now an interdisciplinary team of Yale engineers, physicists and evolutionary biologists has taken a step toward uncovering how these structures form. They compared the nanostructures to examples of materials undergoing phase separation, in which mixtures of different substances become unstable and separate from one another, such as the carbon-dioxide bubbles that form when the top is popped off a bubbly drink. They found that the color-producing structures in feathers appear to self-assemble in much the same manner. Bubbles of water form in a protein-rich soup inside the living cell and are replaced with air as the feather grows.

The research, which appears online in the journal , provides new insight into how organisms use self-assembly to produce color, and has important implications for the role color plays in birds’ plumage, as the color produced depends entirely on the precise size and shape of these nanostructures.

“Many biologists think that plumage color can encode information about quality - basically, that a bluer male is a better mate,” said Richard Prum, chair of the Department of Ecology and Evolutionary Biology and one of the paper’s authors. “Such information would have to be encoded in the feather as the bubbles grow. I think our hypothesis that phase separation is involved provides less opportunity for encoding information about quality than most biologists thought. At the same time, it’s exciting to think about other ways birds might be using phase separation.”

Eric Dufresne, lead author of the paper, is also interested in the potential technological applications of the finding. “We have found that nature elegantly self assembles intricate optical structures in bird feathers. We are now mimicking this approach to make a new generation of optical materials in the lab,” said Dufresne, assistant professor of mechanical engineering, chemical engineering and physics.

Prum believes it was the interdisciplinary approach the team took that led to their success - a result he plans on celebrating “with another practical application of phase separation: champagne!”

Provided by Yale University (news : web)

Explore further: New microscope collects dynamic images of the molecules that animate life

add to favorites email to friend print save as pdf

Related Stories

Fossil feathers preserve evidence of color

Jul 09, 2008

The traces of organic material found in fossil feathers are remnants of pigments that once gave birds their color, according to Yale scientists whose paper in Biology Letters opens up the potential to dep ...

Butterfly Wings Are Templates for Photonic Structures

Dec 11, 2006

By replicating the complex micron- and nanometer-scale photonic structures that help give butterfly wings their color, researchers have demonstrated a new technique that uses biotemplates for fabricating nanoscale ...

Nanojewels made easy

Jul 30, 2008

Butterfly wings, peacock feathers, opals and pearls are some of nature's jewels that use nanostructures to dazzle us with color. It's accomplished through the way light reaches our eyes after passing through the submicroscopic ...

The Unusual Origin of Peacock Brown

Jun 28, 2005

Many animals' colors originate from photonic crystals, which reflect specific colors of light as a result of their nanoscopic structures, rather than from pigments, which derive their colors from their chemical composition. ...

Recommended for you

Scientists develop compact medical imaging device

7 hours ago

Scientists at the MIRA research institute, in collaboration with various companies, have developed a prototype of a handy device that combines echoscopy (ultrasound) with photoacoustics. Combining these two ...

User comments : 0