The chestnut-sided warbler is a New World warbler. They breed in eastern North America and in southern Canada westwards to the Canadian Prairies. They also breed in the Great Lakes region and in the eastern United States.
Region
Eastern North America (breeding); Central America and the Caribbean (wintering)
Typical Environment
Breeds from southern Canada across the Great Lakes and east through New England and the Appalachian region, favoring regenerating clearcuts, shrublands, and forest edges. During migration it passes through much of the eastern United States. In winter it occupies lowland to montane edges, second-growth, and shade coffee or cacao plantations from southern Mexico through Central America and the Greater Antilles. It avoids dense interior mature forest and is most common in brushy, sunlit tangles and sapling thickets.
Altitude Range
0–1800 m
Climate Zone
Temperate
Ease of Keeping
Beginner friendly: 1/5
This small New World warbler thrives in young, shrubby second-growth created by natural disturbance or forestry, and it expanded dramatically with historical clearing in the Northeast. Its classic song is often rendered as “pleased, pleased, pleased to meetcha,” rising and accented at the end. In fall and winter it molts into a much drabber plumage, making identification more challenging. It readily joins mixed-species flocks on the wintering grounds.
Male, Ottawa, Ontario
Adult male, summer (top)Young male (center)Adult, winter (below)
South Padre Island - Texas
juv m or non breeding f - Selva Verde Lodge, Costa Rica
Eating rough prominent caterpillar
Temperament
active and restless
Flight Pattern
short rapid wingbeats
Social Behavior
Typically monogamous on the breeding grounds, with males singing from exposed perches to defend territories. Nests are cup-shaped and placed low in shrubs or saplings, often at forest edges or in clearings. Outside the breeding season it frequently joins mixed-species flocks and forages cooperatively in small groups.
Migratory Pattern
Seasonal migrant
Song Description
A bright, rising series ending with an emphatic accent, often mnemonic as “pleased, pleased, pleased to meetcha.” Calls include sharp chips and softer contact notes used while foraging.
Plumage
Breeding males have a bright yellow crown, white underparts with rich chestnut flanks, a greenish-yellow back with dark streaking, and crisp black facial striping. Females and nonbreeding birds are duller with reduced chestnut on the sides and more olive-washed upperparts. All show two bold white wing bars and clean white underparts.
Diet
Primarily consumes caterpillars, leaf beetles, aphids, and other small arthropods gleaned from foliage and twig tips. It probes curled leaves and actively searches the outer canopy of shrubs and young trees. In migration and winter it supplements with small berries and other soft fruits when insects are scarce.
Preferred Environment
Forages in dense second-growth, regenerating cuts, thickets, and along brushy edges where young deciduous growth is abundant. In winter it uses edges of humid forests, gardens, and shaded agroforestry like coffee and cacao.
