The coloration of a male indigo bunting originates not with pigment but with the diffraction of light around the structure of the bird’s feathers. In good lighting conditions, the bird looks bright blue. In poor light, however, they can look almost black. (Photo by Bryan Stevens)

By Bryan Stevens

The recent five-county Spring Bird Count, conducted Saturday, May 4, by the Elizabethton Bird Club, found 145 species in the five Northeast Tennessee counties of Carter, Johnson, Sullivan, Unicoi and Washington. The count included such cities as Bristol, Johnson City, Jonesborough, Kingsport, Erwin, and Mountain City. A total of 57 participants in 11 parties counted during the annual survey of avian populations in the region. The long-running count is the only spring census of birds conducted in the area.

Not surprisingly, some of the most abundant birds included Canada goose, European starling, American crow, red-winged blackbird and common grackle. Some of the more common songbirds included red-eyed vireo, Northern cardinal, American robin, hooded warbler, American goldfinch and Indigo bunting.

The indigo bunting is one of the reasons spring is such a wonderful time of the year to watch the visitors to feeders. This small songbird likes to reside in the boundary region where forests and woodlands meet fields and pastures. Personally, the indigo bunting has always been a bird that is suggestive of the long, hot days of summer. One of my earliest and still quite vivid birding memories is a recollection of a shockingly blue bird atop a blue spruce tree in my yard. Several decades later, the tree is no longer standing, but these beautiful birds — I now know these summer visitors were indigo buntings — still return each year to my yard and gardens.

These birds usually arrive in the region in late April, and I’ve seen them linger until late October, although most indigo buntings have left the region by late September. Upon arrival, male indigo buntings become tenacious singers, repeating their jumbled notes even during the hottest hours of summer afternoons. The preference of this small songbird is to sing from the tops of tall trees, where they are often concealed by the green leaves. When I do get a glimpse of the obscured songster, often all I see is a dark shape silhouetted against the bright sky. Sometimes, if he plunges from the upper branches into the woodland understory, I get that telltale glimpse of blue feathers.

The indigo bunting is the only solid blue bird in the eastern United States, but it’s all an illusion — literally a trick of the light. The indigo bunting’s feathers are not really blue; the male’s brilliant azure plumage is caused by the process of diffraction of light around the structure of the bird’s feathers. This process scatters all but the blue light, and the resulting color shifts from black to blue to turquoise as the angle of reflected light changes. In bright light, it can even look unnaturally vivid blue. In poor light, however, an indigo bunting male can appear black. Fortunately, indigo buntings have both a characteristic body shape and song, so even if the birds are not seen at their best, they can still be recognized.

Soon after returning to the eastern United States each spring, female buntings begin to gather materials to construct a well-crafted, cup-shaped nest. The male usually stays close to her, but he offers no assistance with nest building. She usually lays a clutch of three to four eggs, but she may nest another two times in a single season.

She will incubate the eggs for almost two weeks, but the young remain in the nest another two weeks after being hatched as featherless, blind and helpless young completely dependent on the care of attentive parents. The task of raising so many broods in the space of only a few months requires the participation of both the female and her mate, who must work hard to bring enough insects to the nest to keep the young fed.

Like many species of songbirds, the male is by far the most colorful. In this instance, the male is also responsible for the species’ name. Indigo is a blue dye that was once an important crop in the South. The drab female may boast some blue highlights in her plumage. Juvenile birds just out of the nest also resemble the female. Pay close attention to any indigo buntings you observe as summer progresses. Juvenile birds will look mostly brown with just a hint of blue in the wings and the tail. These will be the young buntings that were hatched this spring and early summer. They will often accompany their parents to feeders.

Indigo buntings are particularly fun birds to observe in late summer. Although some books indicate that males are not very active in rearing young, I have on numerous occasions witnessed male buntings feeding fledglings at feeders. Indigo bunting juveniles, like the young of many other birds, beg for tidbits from parents by “bowing,” spreading their wings and shivering. These actions usually prompt a parent to pop some morsel into an impatient youngster’s open bill. Indigo buntings are relatively easy to view. They frequent weedy fields and roadside brush. During the breeding season, males can also be seen singing from prominent perches. The song, a distinctive jumble of notes, can help observers find these dedicated singers.

The male indigo bunting is one of the most colorful birds to visit feeders in the region. This species is also extremely fond of millet seed. I like to have some feeders stocked with millet when the buntings begin to return each spring. They will also feed on thistle and sunflower seeds. Away from our feeders, they also devour plenty of seeds from various noxious weeds. Because of the indigo bunting’s appetite for the seeds of destructive weeds, it is considered a beneficial bird.

One of the most attractive summer scenes is to observe American goldfinches and indigo buntings feeding together on the nodding heads of summer sunflowers. The goldfinch males, resplendent in their bright yellow and black plumage, compete with the blue indigo bunting males for the fresh sunflower seeds. When bright red male Northern cardinals join in, observers have a complete artists’s palette for summer viewing.

The indigo bunting will usually respond to human squeaks that imitate a bird’s call. When a flock or family group of buntings are disturbed by a human observer, they usually begin a chorus of alarmed “chipping.”

As I indicated earlier, indigo buntings remain in the region until late September. Although this bird typically winters in Mexico, Panama and the Caribbean, in recent decades some indigo buntings have only gone as far south as Florida to spend the winter. There in the Sunshine State, the indigo buntings may mingle with a close relative, the splendidly multi-colored painted bunting. I usually see these vibrant songbirds whenever I visit coastal South Carolina in spring or summer. Male painted buntings are probably one of the most colorful birds in the United States with hues of red, green, purple and blue in their feathers.

Other North American buntings include the snow bunting, the lazuli bunting and the lark bunting, which is also the official state bird for Colorado. Some of the common but descriptive names for some of the world’s other buntings include rose-bellied bunting, orange-breasted bunting, cinereous bunting, white-capped bunting, lark-like bunting, ochre-rumped bunting, golden-breasted bunting, chestnut-bunting, red-headed bunting, yellow bunting, blue bunting, little bunting, brown-rumped bunting, meadow bunting, corn bunting and crested bunting.

Keep your feeders stocked with millet and sunflower seeds if you want to increase your chances of seeing indigo buntings, as well as other handsome summer songbirds such as American goldfinch, chipping sparrow and Eastern towhee.