American redstarts are small colorful songbirds that belong to a group of warblers. The males in their breeding plumage are unmistakable; they are jet black above apart from large orange-red patches on their wings and tails. Their breast sides are also orange, with the rest of their underparts white. In their other plumages, American redstarts display green in their upperparts, along with black central tails and grey heads. The orange patches of the breeding males are replaced by yellow in the plumages of the females and young birds.
American redstarts breed in North America, spanning southern Canada and the eastern United States. They are migratory, wintering in Central America, the West Indies, and northern South America, and are very rare vagrants to western Europe. During the breeding season, these birds inhabit open-canopy, mostly deciduous forests, second growth, and forest edges. During migration, they occupy a wide range of habitats, including many shrubby areas. On their wintering grounds in Central and South America, redstarts may be found in nearly all woody habitats but tend to avoid non-forested agricultural areas. They are often found in shade-grown coffee plantations, which provide native trees and shrubs, as well as coffee trees.
American redstarts are generally solitary but during migrations will often join groups of different bird species. They are diurnal and very energetic birds spending most of their time on the wing. Redstarts feed almost exclusively on insects which are usually caught by flycatching and may also catch their prey by gleaning it from leaves. They often share their foraging habitats with other warblers and are found feeding in the mid to lower regions of a tree or shrub. Overall, American redstarts are very flexible, opportunistic feeders that can easily adapt to varying habitat, season, insect community, vegetation structure, and time of day. These tiny birds are very vocal; their common song is a series of musical 'see' notes and their call is a soft 'chip'.
American redstarts are carnivores (insectivores) and feed almost exclusively on insects. The diet consists largely of caterpillars, moths, flies, leafhoppers and planthoppers, small wasps, beetles, aphids, stoneflies, and spiders. These birds will also eat some berries and seeds most often from barberry, serviceberry, and magnolia.
American redstarts exhibit a mixed mating strategy; they are generally monogamous and form pairs but some males maintain multiple territories and are polygynous (one male to several females). The breeding season occurs from May until the end of July. Redstarts breed in open woodlands or scrub, often located near water. They nest in the lower part of a bush, laying 2-5 eggs in a neat cup-shaped nest. The clutch is incubated by the female for 10 to 13 days. The chicks are hatch blind, helpless, and almost naked. They fledge after 9 days in the nest and may remain with one parent for up to 3 weeks more. First-year males are able to reproduce during their first breeding season, but their female-like plumage may contribute to low reproductive success until 2 years of age. In contrast, most first-year females successfully reproduce during their first breeding season.
Despite being widespread and abundant, populations of American redstarts decline in many areas due to habitat loss on their breeding and wintering grounds. During their nocturnal migrations, these small birds are often killed by colliding with buildings, telecommunication towers, and wind turbines. They are also vulnerable to both terrestrial and aerial predators; the highest rates of predation occur during the breeding season when eggs and helpless nestlings are abundant and easy prey for varied predators. Females mostly brood during this period and often fall prey to nest predators as well.
According to the All About Birds resource the total breeding population size of the American redstart is 39 million individuals. Overall, currently, this species is classified as Least Concern (LC) on the IUCN Red List but its numbers today are decreasing.
American redstarts feed mainly on insects and thus may control populations of their prey; they also consume some fruits and berries and may disperse seeds throughout their range. Adult redstarts as well as newly hatched chicks and eggs act as a food source to many local predators such as squirrels, chipmunks, American black bears, fox snakes, domestic cats, blue jays, owls, common grackles, and hawks.