Setophaga castanea is a small migratory warbler that breeds in the northeastern United States and southeastern Canada and spends its nonbreeding season in Central America, northern South America, and parts of the Caribbean. It favors mature deciduous and mixed forests during breeding, particularly areas with large tracts of mature hardwoods like maple and beech. In migration and winter, it occupies a broader range of habitats, including tropical lowland forests, forest edges, and shade-grown coffee plantations.

Adult males in breeding plumage are recognizable by their chestnut-colored throat, breast, flanks, and crown, contrasting with a black face, white belly, and two white wing bars. Females and immature birds are less vividly marked, with more muted olive and gray tones and reduced chestnut coloring. The species is about 5 inches long with a wingspan of 8 inches. During breeding, males sing a high-pitched, buzzy song that varies geographically and may help individuals distinguish between neighboring territories. One unusual behavior observed in the species is its preference for foraging high in the forest canopy, where it gleans insects from leaves and branches or makes short aerial sallies to capture flying insects. It also occasionally joins mixed-species flocks in its winter range, especially in humid tropical forests, which may aid in predator avoidance. Setophaga castanea is currently classified as Near Threatened due to steep population declines, largely caused by loss of mature forest in its breeding range and habitat degradation in its wintering grounds. The total population is estimated at fewer than 15 million individuals and is declining.