Setophaga coronata

Family: Parulidae

The Yellow-rumped Warbler is a sturdy, active wood-warbler best known for the bright yellow rump that remains useful for identification even when the rest of the plumage becomes subdued in autumn. In Minnesota it is a regular migrant and breeding resident, with most breeding concentrated in the northern coniferous and mixed forests of the state.

For a photographic account of an autumn encounter, including berry feeding, preening, and open-perch portraits, see Perspective.

Description

Yellow-rumped Warblers are relatively large, full-bodied warblers with a sturdy bill, rounded head, and fairly long, narrow tail. Plumage varies with season, sex, age, and geographic form, but the yellow rump is the most consistent field mark.

In autumn and winter, birds can appear brownish gray above and pale below with dark streaking across the breast and sides. Yellow patches may remain visible on the flanks even when the bird otherwise looks subdued. The face often shows a pale eye ring or broken eye ring, and the folded wing carries contrasting pale markings.

Breeding plumage is much bolder. Adults become grayer and more strongly patterned, with brighter yellow on the rump, sides, and crown. Males are generally more contrasting than females.

The form normally encountered across eastern North America is the Myrtle Yellow-rumped Warbler, which has a whitish throat. The western Audubon’s form typically shows yellow on the throat.

Habitat and Range

Yellow-rumped Warblers breed across much of northern North America, especially in coniferous and mixed coniferous-deciduous forests. In Minnesota, breeding is centered primarily in the northeastern and north-central portions of the state, where spruce, tamarack, pine, and mixed forests provide suitable habitat.

During migration the species becomes much more widespread. Birds move through woodland edges, parks, shrubby areas, open woods, and other places where insects or fruit are available. Fruiting shrubs and trees can become especially important during fall migration.

The Minnesota Breeding Bird Atlas lists the Yellow-rumped Warbler as a regular breeding resident and migrant, with winter occurrence considered accidental.

Identification

The combination of several field marks makes the Yellow-rumped Warbler distinctive:

Bright yellow rump — often the easiest mark to see when the bird turns away, preens, or flies.
Yellow flank patches — usually visible along the sides of the breast, though their intensity varies.
Streaked breast and sides — particularly noticeable in autumn birds against otherwise pale underparts.
Pale throat — characteristic of the Myrtle form commonly encountered in eastern North America.
Pale eye ring or broken eye ring — useful on subdued fall birds.
Contrasting wing pattern — pale wing markings stand out against darker folded flight feathers.
White in the tail — often noticeable when the tail spreads in flight.

Autumn birds can initially appear rather plain, especially at a distance. A brief flash of yellow at the rump or flank is often the clue that resolves the identification.

Similar Species

Magnolia Warbler — Setophaga magnolia

Fall Magnolia Warblers can also appear grayish, streaked, and yellow, but they show yellow more extensively on the underparts and have a different tail pattern. They lack the isolated bright yellow rump patch of a Yellow-rumped Warbler.

Palm Warbler — Setophaga palmarum

Palm Warblers often show yellow beneath the tail and may have a brownish, streaked appearance. Their frequent tail-pumping behavior is useful in the field. They do not show the Yellow-rumped Warbler’s bright yellow rump.

Pine Warbler — Setophaga pinus

Nonbreeding Pine Warblers can overlap in muted color and woodland habitat, but they usually appear less heavily streaked and lack the yellow rump. Their wingbars can appear especially prominent.

Behavior and Ecology

Yellow-rumped Warblers forage actively through trees and shrubs, gleaning insects from foliage and bark and making short flights to capture insects in the air. They often use exposed outer branches between feeding movements.

Their diet changes with the season. Insects and other invertebrates dominate during the breeding season, while fruit becomes increasingly important during migration and winter. Recorded foods include juniper berries as well as bayberry, wax myrtle, poison ivy, Virginia creeper, dogwood, and other fruits.

An unusual ability to digest the waxes in bayberries and wax myrtles allows Yellow-rumped Warblers to use a food source unavailable to most other warblers and helps explain why they can winter farther north than many members of the family.

During migration they may gather in loose flocks, especially where fruit or insects are concentrated.

Notes

An October encounter in Minnesota showed several Yellow-rumped Warblers moving between the upper and lower portions of a juniper.

The upper crown still carried abundant berries, and the birds concentrated much of their feeding there. Lower branches were comparatively bare. Photographs from the upper canopy show a bird working among berry clusters, while later frames show birds returning to more open lower perches.

One lower-branch sequence captured preening behavior. As the bird turned into its back feathers, the bright yellow rump became especially prominent. Other frames showed the yellow flank patch, streaked breast, pale eye ring, and folded-wing pattern against open sky.

The photographs are collected in the Yellow-rumped Warbler Gallery and the companion Photographic Sequence.

References

Cornell Lab of Ornithology. Yellow-rumped Warbler — All About Birds
Cornell Lab of Ornithology. Yellow-rumped Warbler — Identification
Cornell Lab of Ornithology. Yellow-rumped Warbler — Life History
Minnesota Breeding Bird Atlas. Yellow-rumped Warbler — Setophaga coronata