Chestnut-sided Warbler
Setophaga pensylvanica

Conservation status | Apparently far more common today than in early 19th century, with much greater area of second growth brush in East. Numbers may have declined somewhat in recent decades. |
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Family | Wood Warblers |
Habitat | Slashings, bushy pastures. Habitat specialist, expanding range since 19th century as forests were cut over in the eastern United States. Breeds in second-growth deciduous woods, overgrown fields, and edge habitat. Prefers brushy thickets, briers, and brambles. Winters in tropics in forest edge and second growth. |
Photo Gallery
Feeding Behavior
Forages by hopping actively among branches of shrubs and small trees, searching for insects among leaves and twigs, hovering momentarily to take items from foliage. Typically takes insects from undersides of leaves. Also darts out to catch flying insects in mid-air.
Eggs
Usually 4, sometimes 3-5. Whitish with brown markings. Incubated 11-12 days by female. Cowbirds frequently lay eggs in nests of this species. Young: Both parents feed the nestlings. Young leave the nest about 10-12 days after hatching.
Young
Both parents feed the nestlings. Young leave the nest about 10-12 days after hatching.
Diet
Mostly insects. During nesting season, known to eat caterpillars, flies, small moths, small grasshoppers, beetles, spiders; also a few berries. May eat slightly more berries in winter in the tropics, but insects still make up over 90% of diet then.
Nesting
Male sings to defend nesting territory. During courtship, male displays to the female by fluffing his plumage, raising his yellow crown feathers, spreading and vibrating his wings and tail. Nest: Placed in low dense shrubs or tangles, such as blackberry or rhododendron, or in deciduous saplings, such as alder or maple. Loosely constructed open cup nest (built by the female) is made of cedar or grapevine bark strips, fibrous weeds, grasses, roots, and fine plant down, lined with fine grass and animal hair. Nest may be attached to twigs with spiderwebs.
Illustration © David Allen Sibley.
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Text © Kenn Kaufman, adapted from
Lives of North American Birds
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Migration
Mostly migrates at night. Peak migration in most areas is during May and September. Strays appear regularly in West, especially in fall.

- All Seasons - Common
- All Seasons - Uncommon
- Breeding - Common
- Breeding - Uncommon
- Winter - Common
- Winter - Uncommon
- Migration - Common
- Migration - Uncommon
See a fully interactive migration map for this species on the Bird Migration Explorer.
Learn moreSongs and Calls
Rich and musical with an emphatic ending, sometimes interpreted as very very pleased to meet cha!Learn more about this sound collection.