This bird is an impressive songster, singing from sunrise to sunset in the spring and summer. The male sings to establish his territory and attract a mate. He then continues to sing to defend his territory, while the female does most of the work of raising their young. He will sing from several favorite perches, often returning to each of them in a predictable pattern.

Species Description:
Length: 11.4 to 14 cm
Physical characteristics: Only the male has the blue plumage this bird was named for, and it is only present in the breeding season. He also has black on his wings and tail. In the fall and winter he is colored similarly to the female (although he still may wear some blue feathers), with dark brown upperparts and lighter underparts. There is pale dark streaking on the breast and sides of the female and weak wing bars. Males in their first year on territory have varying amounts of white on their bellies and brown feathers amongst the blue feathers of their chest, head and back, ranging from almost completely blue to almost completely brown. This may be a way to reduce attacks from established, territorial males while the new bird locates a vacant territory.
Voice: Song is a high, wispy series of doublets followed by a series of descending doublets and/or some chatter. Song recorded by John R. Sauer. Indigo Buntings compose their songs from a large number of possible phrases. Each male will usually sing the same combination of phrases for its whole life and may share the same combination with from one to over a dozen other neighboring males in a 'dialect' group.

Breeding habitat:
This species frequents brushy and weedy habitats - deciduous forest edge, openings and clearings in woods, overgrown fields and orchards.

Mating system:
Usually monogamous, but can be polygynous; two broods are produced per season.

Nest:
The nest is a well-woven cup of grass, leaves and bark, lined with rootlets and grass; it may also have snakeskin, hair, feathers and Spanish moss included. It is placed in a shrub or tangle .5 - 4.5 meters (1 to 15 feet) from the ground. Only the female builds the nest.

Eggs:
The eggs are pale bluish-white to pure white, and unmarked. Normally 3-4 eggs are laid. 19 mm (0.8″).

Chick development:
The female incubates for 12-13 days. The chicks are hatched altricial. The male may participate in their care, but most often the male does little if any feeding of the young. The chicks fledge in 9-12 days.

Diet:
The diet consists of insects and spiders gleaned from foliage and sometimes from the ground. This bird also eats seeds and fruits.

Parasites:
An undescribed species of feather mite of the genus Trouessartia (Trouessartiidae) and the rabbit tick, Haemophysalis leporipalustris (Packard) have been collected off of buntings caught at Purchase Knob, North Carolina, and Cades Cove, Tennessee, respectively (Reeves et al. 2007). Only two of twelve buntings checked in 2006 had feather mites of some kind.

Eggs of an unidentified louse were observed on an Indigo bunting in the Park in 2007.
Parasites of the genus Leucocytozoon, a parasitic protozoan that circulates in the host?s blood and infects internal organs, were visually confirmed in a blood sample from a bunting caught in Cades Cove in 2001 (det. P. E. Super). Examinations of fecal samples collected from buntings caught at Purchase Knob (C. Faulkner, V. Faulkner, S. Stone, and K. Myers; 2003-2006) detected oocysts of an unidentified coccidian parasite of the genus Isospora (Eimeriidae) and eggs of an unidentified tapeworm.

Conservation Biology:
The abundance of the Indigo Bunting across much of its range has increased since the early 1900?s as logging and the abandonment of farmland have increased favored habitat. Populations may decline with repeated mowing of roadsides and farms, urbanization and succession of old farmland into forest.

The Indigo Bunting is frequently parasitized by the Brown-headed Cowbird. Occasionally this host bird will bury the cowbird eggs in a new layer of nesting material.

Breeding: The Indigo Bunting is found across the eastern half of the United States (excluding the southern tip of Florida) and into southern Canada. It also breeds in some areas of New Mexico, Arizona, Utah, and California.
Winter: This species is a neotropical migrant that winters in southern Florida, the Bahamas, the West Indies and southern Mexico, south through Central America to Colombia and Venezuela. It often forms winter flocks with other species of finches.

The Indigo Bunting is a very common breeding bird in the Park. It is common at all elevations and is most often observed singing in forest openings, especially on the western half of the Park.

A survey of breeding birds in the Park, performed from 1996-1999, ranked Indigo Bunting as the 15th most common species out of 113 species observed during the breeding season. Estimates from this survey indicate that overall Indigo Bunting density in the Park during the breeding season is 0.17 pairs per hectare with highest densities occurring between 2,000 - 3,000 feet.

References:

Alsop, F. J. III. 1991. Birds Of The Smokies. Great Smoky Mountains History Association, Gatlinburg, Tennessee.

Bent, A. C. and Collaborators. 1996 - 2002. Indigo Bunting, In Life Histories of Familiar North American Birds, ed., Patricia Query Newforth.

Committee on Classification and Nomenclature of the American Ornithologists' Union. 2002. Forty-third supplement to the American Ornithologists' Union Check-list of North American Birds. The Auk 119: 897-906.

Ehrlich, P. R., D. S. Dobkin, and D. Wheye. 1988. The Birder's Handbook: a Field Guide to the Natural History of North American Birds. Simon and Schuster, Inc., New York.

Elphick, C., J. B. Dunning, Jr., and D. A. Sibley, eds. 2001. The Sibley Guide to Bird Life and Behavior. Alfred A. Knopf, New York.

Gough, G. A., Sauer, J. R., Iliff, M. Patuxent Bird Identification Infocenter. 1998. Version 97.1. Patuxent Wildlife Research Center, Laurel, MD.

Payne, R. B. 1992. Indigo Bunting. In The Birds of North America, No. 4 (A. Poole, P. Stettenheim, and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists' Union.

Reeves, W. K., L. A. Durden, C. M. Ritzi, K. R. Beckham, P. E. Super, and B. M. O'Connor. 2007. Ectoparasites and other ectosymbiotic arthropods of vertebrates in the Great Smoky Mountains National Park, USA. Zootaxa.

Sibley, D. A. 2000. The Sibley Guide to Birds. Alfred A. Knopf, New York.

Stupka, A. 1963. Notes on the Birds of the Great Smoky Mountains National Park. University of Tennessee Press.