Photo: Rick & Nora Bowers/Vireo

Chestnut-sided Warbler

Setophaga pensylvanica

In leafy second-growth woods, clearings, and thickets, this warbler is often common, hopping about in the saplings with its tail cocked up at a jaunty angle. It is apparently much more numerous today than it was historically: John James Audubon, roaming eastern North America in the early 1800s, saw this bird only once. The cutting of forests evidently has created more brushy habitat for Chestnut-sided Warblers, even as it has made other birds less common.
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.
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.
In leafy second-growth woods, clearings, and thickets, this warbler is often common, hopping about in the saplings with its tail cocked up at a jaunty angle. It is apparently much more numerous today than it was historically: John James Audubon, roaming eastern North America in the early 1800s, saw this bird only once. The cutting of forests evidently has created more brushy habitat for Chestnut-sided Warblers, even as it has made other birds less common.
Photo Gallery
  • adult male,breeding
  • adult female, breeding
  • immature female, 1st winter
  • adult male, breeding
  • adult female, breeding
  • immature female (1st winter)
  • breeding pair and nestlings
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.
Learn more about these drawings.

Text © Kenn Kaufman, adapted from
Lives of North American Birds

Migration

Mostly migrates at night. Peak migration in most areas is during May and September. Strays appear regularly in West, especially in fall.

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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
Songs and Calls
Rich and musical with an emphatic ending, sometimes interpreted as very very pleased to meet cha!
Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
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How climate change could affect this bird's range

In the broadest and most detailed study of its kind, Audubon scientists have used hundreds of thousands of citizen-science observations and sophisticated climate models to predict how birds in the U.S. and Canada will react to climate change.

Learn more

Read more: climate.audubon.org
Wood Warblers Perching Birds

Chestnut-sided Warbler

The darker the color, the more favorable the climate conditions are for survival. The outlined areas represent approximate current range for each season.

More on reading these maps.

Each map is a visual guide to where a particular bird species may find the climate conditions it needs to survive in the future. We call this the bird’s “climatic range.”

The colors indicate the season in which the bird may find suitable conditions— blue for winter, yellow for summer (breeding), and green for where they overlap (indicating their presence year-round).

The darker the shaded area, the more likely it is the bird species will find suitable climate conditions to survive there.

The outline of the approximate current range for each season remains fixed in each frame, allowing you to compare how the range will expand, contract, or shift in the future.

The first frame of the animation shows where the bird can find a suitable climate today (based on data from 2000). The next three frames predict where this bird’s suitable climate may shift in the future—one frame each for 2020, 2050, and 2080.

You can play or pause the animation with the orange button in the lower left, or select an individual frame to study by clicking on its year.

The darker the color, the more favorable the climate conditions are for survival. The outlined areas represent approximate current range for each season. More on reading these maps.
Winter
Summer

Winter Range
Summer Range
Both Seasons
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