High-maintenance mallards

Jun 17, 2011
A mallard displays the vivid colors of its speculum feathers. Credit: Rafael Maia.

The shimmery feathers of a male mallard might have a showy quality that appeals to prospective mates, but the water resistance and self-cleaning capabilities of iridescent feathers pale in comparison to those of noniridescent plumage.

"Those good looks come at a cost," says researcher Chad Eliason, a graduate student in The University of Akron Integrated Biosciences Ph.D. program. Eliason, along with principal investigator Dr. Matthew Shawkey, UA associate professor of biology, say mallards' patches of iridescent feathers have deficient .

The Journal of Experimental Biology selected Shawkey and Eliason’s research finding, "Decreased hydrophobicity of iridescent feathers: a potential cost of shiny plumage," as its Editors' Choice paper for the July 2011 issue of the journal.

Eliason explains that iridescent feathers achieve their color by light scattering from nanometer-scaled structures in the plumage. The flattened barbules of thesefeathers are twisted toward the plumage surface, causing them to reflect light in abundance, yet expose more surface area for water adhesion.

"The deeper the tone of the iridescent feather, the less its hydrophobicity," says Shawkey, adding that less water resistance not only results in damp, but also soiled feathers.

Pretty, not practical

Eliason and Shawkey exposed both dull brown and iridescent violet portions of feathers to water droplets and discovered that the brown plumage repelled water, which efficiently washed away dust. In contrast, vivid violet feathers retained more water, compromising their ability to self-clean.

The researchers add that their finding provides insight to the evolution and distribution of iridescent plumage in birds.

"Males may use iridescent colors to advertise to prospective mates their ability to survive despite potentially waterlogged feathers; then females could correctly choose high-quality males," says Shawkey. “These flattened barbules are found in iridescent of many species, so this could be a widespread pattern. We hope to find out if this is true in future research."

Explore further: Survey debunks myth of 'flying ant day'

Provided by University of Akron

4 /5 (1 vote)

Related Stories

The role of color in animal courtship uncovered

Dec 15, 2010

Researchers at UQ's Queensland Brain Institute are one step closer to unlocking the role of color in animal courtship rituals after identifying a unique feather structure in birds of paradise.

Recommended for you

Smarter than a first-grader?

8 hours ago

In Aesop's fable about the crow and the pitcher, a thirsty bird happens upon a vessel of water, but when he tries to drink from it, he finds the water level out of his reach. Not strong enough to knock over ...

How honey bees stay cool

20 hours ago

Honey bees, especially the young, are highly sensitive to temperature and to protect developing bees, adults work together to maintain temperatures within a narrow range. Recently published research led by ...

User comments : 0