To Blue or Not to Blue

Bucko wrote, "Hmm, Kengineer is skeptical about the lack of blue in the feathers.  Looking at the cool one you framed, at various angles, I will admit the amount of blue depends on the refraction angle, but I believe there is a blue base.  I believe additional research is required :o)"

 

Ahh, the gauntlet has been thrown!

 

According to Mark Johns, on the staff of North Carolina Wesleyan College:

 

"Interestingly enough, the blue and iridescent colors in birds are never produced by pigments and are actually structural colors. The blues are produced by minute particles in the feather that are smaller in diameter than the wavelength of red light. These particles are able to influence only shorter wavelengths, which appear blue and scattered (reflected) in all directions. This blue color remains stable at all angles in reflected light, unless the bird gets between the light and observer."

 

On Birdwatchers.com, an article about the apparently blue feathers states:

 

"Within the ability of our eyes and brains to interpret colors, most of these birds appear plainly blue. And that is okay, and true, inasmuch as our dependable eyes tend to send to our brains only the information that they receive. In the sense of spectral color coming from these bird’s feathers that information is blue color.

 

But wait, there is a best part…throughout the entire world, and the known galaxy, there isn’t a single blue feather being naturally sported by any bird! So, where does this blue color come from? Is it some sort of optical illusion? It is! But more than that, it is two optical illusions.

The physics of it is that objects can - in a simplistic fashion - absorb and reflect light. The absorbed color is negated. The reflected light is invisibly sent off into space. If, by chance, however, this reflected light is caught by an eye, and subsequently interpreted by a brain, then it becomes color. Like all feathers, blue ones can reflect light in a couple of ways. If the surface is smooth - microscopically smooth - it can allow the pigment inside of the feather to dominate the reflection. This takes place on the molecular level and involves a bit of a prismatic effect.

Prisms are neat. It seems like they can take any light and turn it into a rainbow. But some specifically deformed prisms can retain certain colors and only reflect others. Pretty sneaky, huh? So, even a black-pigmented feather can look blue! Most blue birds have smooth-surfaced feathers, and the absorption and reflection of light takes place inside the feather. The outcome can be quite spectacular. Just picture all the tones of blue on a blue jay. Now, there’s a prismatic work of art - especially given that the bird does not have a single blue feather on its body."

Kinda mind-boggling, isn't it? And what a complex and fascinating world, where blue birds are not truly blue...but we THINK they are. Whoa. That is some weird, wild stuff.

May you all be visited this weekend by the Faux Bluebird of Happiness! 

 

Tags: Blue feather pigment