Chestnut-sided Warbler
Chestnut-sided Warbler
Setophaga pensylvanica
At a Glance
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.
All bird guide text and rangemaps adapted from Lives of North American Birds by Kenn Kaufman© 1996, used by permission of Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Category
Perching Birds, Wood Warblers
IUCN Status
Least Concern
Habitat
Fields, Meadows, and Grasslands, Forests and Woodlands, Shrublands, Savannas, and Thickets
Region
California, Eastern Canada, Florida, Great Lakes, Mid Atlantic, New England, Northwest, Plains, Rocky Mountains, Southeast, Southwest, Texas, Western Canada
Behavior
Direct Flight, Flitter
Population
18.000.000
Range & Identification
Migration & Range Maps
Mostly migrates at night. Peak migration in most areas is during May and September. Strays appear regularly in West, especially in fall.
Description
5" (13 cm). Yellow cap, black face stripe around white cheeks, ragged chestnut stripe on sides. In fall, very different: lime green above, white below, with white eye-ring on pale gray face, two yellow wing-bars; may or may not show some chestnut on sides.
Size
About the size of a Sparrow
Color
Black, Green, Red, White, Yellow
Wing Shape
Rounded
Tail Shape
Notched, Square-tipped
Songs and Calls
Rich and musical with an emphatic ending, sometimes interpreted as very very pleased to meet cha!
Call Pattern
Flat, Undulating
Call Type
Chirp/Chip, Hi, Whistle
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.
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Behavior
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.
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.
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.
Conservation
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.
Climate Threats Facing the Chestnut-sided Warbler
Choose a temperature scenario below to see which threats will affect this species as warming increases. The same climate change-driven threats that put birds at risk will affect other wildlife and people, too.