Species profile: Spring's vibrant singer, Indigo Bunting
The Indigo Bunting, a member of each spring's dawn chorus, carries its lively tune long into each summer
Published: May 1, 2005
|Every morning for the past 35 years, I have walked the road around the lake on which I live in southeastern Wisconsin for both exercise and birding. During all those years, I have observed the changing seasons, especially by watching birds.|
No period during the four seasons is more delightful than spring, when the dawn chorus of birdsong is at full volume, indeed, at a fever pitch. Buried among the songs of warblers, finches, thrushes, orioles, and tanagers, I listen for an Indigo Bunting. I may hear as many as three males singing as I walk the mile-and-a-half blacktop road around the lake. Though all the songsters in the chorus are delightful to hear, the Indigo Bunting's song is very special for me. I take exceptional delight when the first male appears in a thicket in early May. It seems to proclaim, "I have arrived."
Describing the song of the male Indigo Bunting is difficult. It's a combination of whees and zeeres. David Sibley describes it as "fire fire where where here here." Roger Tory Peterson said the song is "lively, high, and strident, with well-measured phrases at different pitches; notes usually paired: sweet, sweet, chew, chew, etc." Its alarm note is a sharp, thin spit.
The Blue Beauty...
I heard a great many of those spit alarms while trying to photograph a pair of buntings at their nest in southern Ohio a few years ago. The nest was lovely, built well of grass about three feet above the ground in the crotch of a small shrub. From a blind 30 feet away, I was able to shoot photo after photo of the female feeding her four nestlings. Though she is a lovely bird in plain light-brown feathers, faint stripes on her breast, and a hint of blue in her wings and tail feathers, she is not the dandy that her all-blue mate is. For that reason, I was determined to wait him out. Surely he would feed something over the couple of days I had allotted to the project. Finally, totally confused and discouraged about failing to get a single photo of the male at the nest, I telephoned my father from the blind on my cell phone. He had photographed Indigo Buntings at their nests many times.
"Dad, why doesn't this male Indigo Bunting feed his young?" I asked.
"Because male Indigo Buntings don't feed at the nest," he responded.
"Never?" I asked.
"Not in my experience," he said.
With all due respect to the old man, I have since seen at least one photo of a male bunting feeding at the nest, but apparently it is very unusual. So I folded my tent and gave up my dream of photographing the gorgeous blue bird at its nest.
Not long after that, I took some acceptable pictures of a male bathing in my re-circulating birdbath. But the wetter the bird got, the less blue he appeared to have in his feathers. In fact, when he was totally wet, he seemed to be a black bird, not a blue bird. What was going on here? I seemed to be jinxed every time I tried to photograph the bunting.
...Is Really Brown?
A little research into the blue feathers of the Indigo Bunting was very revealing. I learned that the male bunting isn't really blue at all. It's brown. John K. Terres, author of the Audubon Society Encyclopedia of North American Birds, describes certain feather colors as "optical illusions." "Many of the colors we see in birds are a result of various rainbow colors of the spectrum being either reflected or absorbed as light falls on a feather and bounces back to the observer's eyes," he writes. "Apparently, blue is never the result of blue pigment. For example, the bright blue of the Blue Jay, bluebirds, and the Indigo Bunting is [from] light waves of blue reflected from a layer of cells which overlies the dark, brownish basal pigment cells in the barbs of the feathers." Wow! How's that for a Jeopardy answer? Blue birds look blue just because their feathers reflect the blue light in the sky.
Take it from me, though. My first-ever sighting of an Indigo Bunting, as a boy in Pennsylvania, perfectly illustrates the point. It was a hot July afternoon when I spotted the spectacular bird perched on the top branch of a roadside apple tree, singing its paired notes in a high-pitched voice. A few days later, on a rainy afternoon, I heard the bird again in the same apple tree. I looked in vain for the bright blue bird, but on that dark, rainy day, the bird singing the song of an Indigo Bunting was brown, almost black. It was not until many years later that I learned why the wet bird appeared so different. The same thing happens when an Indigo
Bunting is perched between the sun and me. The dark side of the bird is brown.
As the summers along my lake road wear on, and the enthusiasm of the dawn chorus peters out, usually just two species carry on singing as if spring had just arrived - the Red-eyed Vireo and the Indigo Bunting - but by then, they are no longer part of a cacophony of avian singers. By late summer, they are all that is left of the chorus. I have often been thankful for the bunting's song on an August morning, because it seemed to be the last remnant of the vibrant sounds of spring. When the Indigo Buntings finally go quiet, summer has ended.
Did you know?
Plumage: Male Indigo Buntings in their first breeding season appear brown with variable amounts of blue and white. By their second spring, males are all blue. This molting cycle is known as delayed plumage maturation.
Buntings meet up: Where Indigo and Lazuli Bunting breeding ranges overlap in the West, the birds sometimes hybridize.
Differences: Except for size, wing bars, and bill shape, Indigo Buntings and Blue Grosbeaks are very much the same in appearance. Even their eggs are similar.
Winter range: Indigo Buntings winter in southern Florida, southern Mexico, Central and South America, and the West Indies. Males depart for their breeding grounds about two weeks before females do.
Feeder preferences: Indigo Buntings will eat cracked sunflower and nyjer (thistle) seeds at bird feeders.
|George H. Harrison writes from his home in Hubertus, Wisconsin.||