Older males are glossy black with red patches on the outer tail, at the base of the wing, and on the sides of the breast. Younger males are intermediate in color between the male and female. The female has yellow where the male has red, and is lighter in color. Bill and legs of the male and female are brown to black. 11-13 cm (4-5 in) in length.
Breeding season starts in May and extends through July. Pair formation occurs once the females arrive on the breeding grounds. The female builds a woven cup-shaped nest. It is usually in low shrubs or saplings, but can be at a variety of heights (3-6 m, 10-20 feet). The female lays one egg each day until the clutch is completed (usually 3-4 eggs). The female incubates the eggs for 11 days. The male will feed the female while she incubates the eggs. The young are altricial, and will remain at the nest for 9 days. Young are cared for by both the male and female while in the nest and for a short time (a few days to a few weeks) after they leave the nest.
The American Redstart is a hardwood forest bird, using bottomland forests and swamps in the Coastal Plain and hardwoods along streams in the mountains. It forages at all heights within the forest, eating a variety of insects including leafhoppers, planthoppers, flies, wasps, beetles, moths, and caterpillars. This species is a rapid forager, using a distinct technique of "flashing" its wings and tail to flush prey. Once the prey is flushed, the Redstart chases it acrobatically through the air to capture it. Occasionally a Redstart will also eat small berries and fruit. This species is migratory. Adults arrive on the breeding grounds in late April to early May.
The American Redstart breeds in most of the eastern and northern United States and Canada within suitable habitat. It nests in the northern and western portions of Georgia. This species migrates, leaving the breeding grounds starting in July to winter in the Caribbean and in Central and South America. During migration it is found throughout Georgia in suitable habitat.
The American Redstart is not listed as Threatened or Endangered in the Southeast. However, habitat destruction may attribute to the decline of this species, because when habitat is fragmented, more predators and parasites like the Brown-headed Cowbird have access to interior forests. The fragmented land may give them nearby places to eat or easier traveling.
Among the warblers, the color pattern of the American Redstart makes it unique. Another species which appears similar is the Black-throated Blue Warbler which has a dark blue appearance overall and white patches on the wings and tail.