For the Birds Radio Program: Blue Feathers, and Baker's Blue Jay Barn
Of all the colors of the rainbow, blue is the oddest, at least in the world of birds. If you found a red feather from a cardinal or Scarlet Tanager and ground it in a blender, you’d end up with a reddish powder. Do the same for a yellow feather from a goldfinch, warbler, or flicker, and you’d get a yellow powder. That’s because these colors are caused by chemical pigments.
But if you ground up a blue feather from a jay, Indigo Bunting, or bluebird, you’d end up with a dull brown powder. Birds with blue feathers get their color from a layer of cells overlaying the brown pigment in the feather. As light hits the feather from any angle, this layer of cells scatters the short wavelengths, making the feather appear blue. But if you backlight a blue feather by holding a light behind it, the feather appears dark brown showing only the actual pigment of the feather. All blue feathers get their color this way.
Blue is not the only structural coloration found in birds. Iridescence is also caused by the structure of the feather rather than by pigments. The brilliant red of a hummingbird’s throat feathers is lost completely when the feather is backlit or ground up. In fact, just changing the angle of an iridescent feather changes the way light is reflected, changing the color. A Ruby-throated Hummingbird’s throat appears black or red, depending on how the light hits it. How does iridescence work? The tiny hairlike parts of an iridescent feather, the barbules, are flattened and twisted. As the flat sides are turned to face the observer, the light they refract and reflect is of only one specific wavelength—red, in the case of the hummingbird.
Feathers with flattened and twisted barbules are missing some of the hooklets and flanges that normally zip the barbules together. This means that iridescent feathers are not as strong as other feathers, and so birds never have fully iridescent colors in their flight feathers. Even the iridescent speculum feathers on a duck’s wings are bordered with black, and are on the part of the wing that is least mechanically stressed by flight.
Feathers are a perfect marriage of form and function, giving a bird insulation against cold and heat, strength to support its weight in flight, and beauty to boot. Yes, feathers are one of nature’s true miracles.
(Baker’s Blue Jay Barn advertisement)
This is me, Jim Baker. You know, even though some Blue Jays spend the whole winter in the north woods, others prefer to travel now and then. And when they first arrive in a new area, they can feel downright overwhelmed searching for a warm, safe place to eat and sleep.
If you see a jay looking for a place to spend the night, send him on over to Baker’s Blue Jay Barn. My spacious rafters are just the place for a jay to meet new friends gathering for gossip and companionship. After a long journey, a few jays do prefer quiet, secluded quarters, so I built some private rooms just for them. And for those romantic jays who’ve just tied the knot, there’s my Blue Jay Honeymoon Suite, with a heart-shaped bird bath and a complimentary bottle of champagne. Of course it’s empty—a Blue Jay hardly needs alcohol to have a jolly time—but they have a lot of fun figuring out how to pry the cork out with their beaks, and they sure get a kick out of the popping sound it makes.
Yep. Send your favorite Blue Jays on over to Baker’s Blue Jay Barn—a Blue Jay’s home away from home. We’ll leave the light on.