Nov/Dec 2007For Wildlife Watchers: Indigo buntingby Rob Simbeck, photography by Jeff Mollenhauer
Most of us shy away from scientific inquiry. Pursued with any real vigor, we fear, it can only mess things up. Take the rainbow. Examined closely, it's nothing more than the interaction of light waves, water droplets and the human eye. Philosophically speaking, given the concepts of primary and secondary qualities, it isn't really there. Bring that up, though, as you and your sweetie are looking at one and you are certain to kill whatever magic those airborne colors have created.
There are those, though, and I am one of them, who figure that awareness of the science and philosophy behind an experience can deepen rather than spoil it, adding an intellectual thrill to the sensual. And so, aware of the risks, I feel it's my duty to report that, in the spirit of the rainbow, there are no blue birds. Now, since I realize you just looked again at the gorgeous photo of the indigo bunting above this, let me rephrase that: there are no blue pigments in the feathers of blue jays, bluebirds or, in the case at hand, indigo buntings.
Indigo bunting - Passerina cyanea "Dark blue sparrow like"
Appearance: In sun, breeding males appear brilliant blue, with darker crown and black feathers in tail. Females, young and wintering males are brown.
Range and Habitat: Gulf Coast to southern Canada and across the Southwest. Brushy edges, abandoned farmland.
Nesting and Young: Nesting begins in May. Two or more clutches. 3 to 4 eggs normally, up to 6 possible.
Viewing Tips: Listen for the energetic song in brushy areas and look for the often conspicuously perched male.
The explanation can get awfully long-winded (Would it be science or philosophy otherwise?), but an indigo bunting's blue is what is called a structural color. The underlying pigment, melanin, is brown, but the feather's microscopic make-up causes different wavelengths of light to bounce in different directions, giving it a variable appearance. Backlit or in the shadows, an indigo bunting looks almost black. In direct sunlight - bingo! - those lovely indigo rays hit your eyes or a camera lens. It's analogous to the way the sun, which shines white light, looks red, orange or yellow, depending on how much atmosphere that light is traveling through.
All of this, by the way, applies about half the time, since it's in the adult male that the indigo shows up. In females and juveniles, the operative color is brown, with just a few blue streaks in the tail and some faint breast streaks.
About five inches long, the indigo bunting is a finch with a fondness for brush and weeds, where it can be seen feeding on seeds and insects. It thrives in abandoned fields and forest clearings, and along weedy roadsides, which abound in the Palmetto State.
"I always think of indigo buntings as a real indicator of early successional habitat," says Laurel Barnhill, a wildlife biologist with the Department of Natural Resources. "Build it, and they will come. Along roadways, even in heavily forested areas, if there's light enough to grow shrubby habitat, the indigo buntings will be singing there."
The singing begins each year with the males' arrival in late April or early May from their winter homes in South America and the Caribbean. They await the females, singing a warbling, double-note song to stake out territory and then in courtship, when they often sing all day long.
"Their song is really unique," says Barnhill. "When we teach bird identification, we render it as Fire! Fire! Where? Where? Here! Here! See it! See it! They'll be near the thick, shrubby stuff, singing from about eye level to twelve feet or so. They really make their presence known."
The nest, built by the female, is a cup constructed of woven grass, leaves and twigs from 3 to 10 feet off the ground in a bush, hedge or sheltering tree. The female lays three to four bluish-white eggs and incubates them for twelve or thirteen days. The male brings food and defends the nest and chicks, relieving her of nest duties on occasion. The young fledge after eight to ten days, and the adults will often produce a new clutch, sometimes with other mates.
Indigo buntings migrate south again as the weather cools, traveling in flocks at night and navigating, in part, using stars. They form large flocks in their winter homes, foraging and roosting in groups that may number thousands of birds.
They are sold as caged songbirds in Europe and Mexico and are often killed for food or sport in their wintering grounds. Here, it is sprawl that threatens them, constantly nibbling away at their favorite feeding and nesting places. Even so, their habitat needs dovetail nicely with current conditions in the state, and it's thought that, like mockingbirds, indigo buntings are probably more numerous now than they were when Europeans landed. Given their seemingly healthy population in South Carolina, it is easy to enjoy the songs and beauty - illusory though it is - of this magnificent little bird.