Indigo Bunting

The Indigo Bunting is one of the best known songbirds in Eastern North America and is closely related to it’s counter part the Lazuli Bunting (Passerina amoena) of Western North America. It is a small migratory species that breeds in the eastern part of the continent and winters primarily in southern Florida, Mexico and Central America, and on islands in the Gulf of Mexico. It is rare in the West.

Adult Male (spring/summer)

Deep blue overall; older males are bright blue, the head somewhat more purplish blue; dark gray conical bill. In winter is brownish, with some blue on underparts, wings and rump.

Adult Female (spring/summer)

Brown often with a touch of blue on the shoulders, rump and tail; faint wing bars and faint streaking; short, gray, conical bill.

Juvenile

Juvenile males mostly pale brown, blue patches on breast and wings.

General:

Rather stocky, short-tailed and small-billed bunting with dark conical bill.
Length: 14 cm. Wing: 20cm. Weight: 14.5 g.

Behaviour:

Forages on the ground, in low foliage, in trees, shrubbery; eats grasshoppers, beetles, weevils, aphids, cicadas, cankerworms, flies, mosquitoes; seeds of dandelion, golden-rod, aster, thistle, grasses; small grains, berries. Male strongly defends his territory against other males by singing from trees, utility wires and other perches.

Habitat:

In summer lives in weed-grown fields, forest edges, roadsides, hedges, dry brush-lands, orchards, open woods of dry uplands, along creeks and rivers with thickets for nesting, highway, power line, and railroad rights-of-way.

Information:

The adult male in breeding plumage is the only small N. American finch to appear blue all over. The male in sunshine is almost solidly blue, but against the sky or in shade may appear black. Sometimes hybridizes with Lazuli Bunting. The nest is of dead leaves, weed stems, grasses, lined with finer grasses and downy material, and is placed in the fork of a shrub branch or tangle or in a tree, two to ten feet above the ground. Two to six white eggs are laid.

Similar species: Lazuli Bunting

Conservation Status:

Numbers are declining. Listed as Least Concern.

Capture Rates

The habitat of Colony Farm is well suited to the Indigo Bunting and though its range may be expanding it is a rare visitor to the west. This is reflected in low capture rates with two individual males captured at the banding station.

Molt Summary:

PS/PF: HY incomplete (Jun-Dec); PB: AHY complete (Aug-Oct); PA partial-incomplete (Jan-May).
PS: occurs in some or all HYs with the body plumage being replaced once on the summer grounds in Jun-Oct . Occasionally includes the innermost gr cov, but no tert or rects.
Preformative molt occurs on the winter grounds with flight feathers in Oct-Dec. Is eccentric with all gr covs, the outermost 2-7 pp, the innermost 2-5 ss, the outermost 0-2 pp covs, and rects replaced.
Adult PB: begins on the summer grounds, but most molting occurs during migration or on the winter grounds.
1st PA: includes 0 – 9 inner gr covs and sometimes 1 – 3 terts and/or s6, but no rects. Occurs primarily on the winter grounds, but often completes on the summer grounds.
Adult PA: includes 5 – 10 inner gr covs, often 1 – 3 terts, and occasionally 1 – 4 central rects.

Buntings often have an extensive preformative molt including all lesser, median and greater coverts, carpal covert, alula, tertials, additional inner secondaries and outer primaries. Members of the Cardinalis family like Grosbeaks and Buntings where males have such contrasting and distinctive plumages are very helpful for learning molt patterns and especially helpful in looking for molt limits in females of the same species.

The wing of the SY male below shows distinctive contrasts between 3 generations of feathers; juvenile, formative and first alternate and illustrates the eccentric pattern of replaced remiges (primaries and secondaries) common in this species.

In its preformative molt following the breeding season last year this bird replaced lesser and most median coverts, all but two of its greater coverts (GC 3 & 10 illustrated with the green arrows – GCs are numbered proximally towards the birds body with GC10 the innermost), the carpal covert, alula, the outermost primaries (pp 5-9 – primaries are numbered distally away from the birds body with p9 the outermost) but no secondaries or tertials. The preformative molt limit is indicated with the red arrows – notice the thick glossy, black rachis of the replaced outer primaries easily distinguishing them from the retained juvenal inner primaries and secondaries. In its 1st prealternate molt in the late winter / early spring it replaced inner greater coverts 7-9, tertials and the innermost secondary (S6) indicated by the blue arrows.

Finally notice the washed out, worn and lightly pigmented appearance of the retained juvenal feathers especially the now very worn and tapered primary coverts.