About us: We own the Wild Birds Unlimited nature shop in East Lansing, Michigan,
a store that provides a wide variety of supplies to help you enjoy the birdwatching hobby.

This blog was created to answer frequently asked questions & to share nature stories and photographs.
To contribute, email me at bloubird@gmail.com.

Wednesday, February 3, 2010

Eastern Bluebird: Carrier of the Sky

"The Bluebird carries the sky on its back" -- Henry David Thoreau

It would be hard to find anything as dazzling as a Bluebird standing on a fence post in the early morning sun. Its brilliant blue plumage might even be said to rival the sky itself. Too bad it's just one big illusion! It's true! Bluebirds aren't really blue . . . they just look like they are!

Most bird colorations are due to pigments deposited in their feathers. A Northern Cardinal is red because of the red pigment called carotenoids. Crows are black because their feathers contain a dark pigment called melanin. In contrast, Bluebirds do not have a single molecule of blue pigment in any of their feathers. So where does that brilliant blue color come from?

The answer is that the color is not produced by a pigment, but by the structure of the feather. The top transparent layer of each blue feather is filled with minuscule pockets of air. When sunlight strikes these pockets, all of the other visible wavelengths of light are absorbed. Only blue escapes and it is scattered in all directions. This same scattering process, created by atmospheric dust particles, is also what makes the sky appear blue.

So Thoreau was right . . . Bluebirds literally do carry the sky on their backs.
Source: WBU Bird of the month: http://www.wbu.com/botm/botm_0308.html

3 comments:

cindyzlogic said...

Cool post! We're still trying to attrack the Eastern Bluebird to our yard :-)

Wild Birds Unlimited Mid-Michigan said...

Bluebirds would be nice! People come in the store all the time with wonderful bluebird stories.

My wooded yard isn't designed for bluebirds but I'm lucky the local nature center has a nice bluebird trail that I enjoy.

Joy K said...

I was talking to one of my 5th grade students about this, and mentioned that if you crush the feathers, the color disappears.

She was horrified. "Well, THAT would be MEAN!!" Apparently, she had visions of me smashing the feathers while they were still attached to the bird.