Details

Chestnut-sided Warbler
Setophaga pensylvanica

As the name implies, this distinctively marked warbler of shrubby and edge habitats has a beautiful chestnut-colored streak on its sides. This bird was rare during John James Audubon's time, but increased during the 19th century when logging and low intensity agriculture provided an abundance of early successional habitat. The Chestnut-sided Warbler can be found throughout Tennessee during spring and fall migration, but nests only in the mountains in the eastern portion of the state. The breeding range extends from south-central Canada to Nova Scotia, south to southern Pennsylvania, and along the Appalachian Mountains to northern Georgia. In winter, it joins mixed species flocks with other migrants and resident birds on the wintering grounds in Mexico and Central America.

Description: In breeding plumage, the Chestnut-sided Warbler has a yellow forehead, white underparts with a chestnut streak along the sides, a black line through the eye, a black mustache-strip, 2 broad yellowish wing-bars, and the back is striped yellow and black. The female has a similar pattern but is duller with a greener back, paler face, and less extensive chestnut on the sides. The plumage changes dramatically during the fall and winter (August-March). During the non-breeding season the underparts are plain white, the upperparts are greenish yellow, and both sexes have an obvious white eye-ring. Its habitat of frequently cocking its tail, like a wren or gnatcatcher, is a good identification aid.
Length: 5"
Wingspan: 7.75"
Weight: 0.34 oz

Voice: The song is often described as a whistled pleased pleased pleased to mEEchew.

Similar Species:

• No other warbler has the combination of a greenish-yellow cap, a white breast, and reddish streaks down the sides.
• The Bay-breasted Warbler has chestnut on its sides but also on the head and chest in breeding plumage. During the non-breeding season the plumage is more dingy, lacking the contrast between the bright yellow-green upperparts and white underparts of the Chestnut-sided Warbler.

Habitat: Breeding habitat is shrubby second-growth and forest edges, including abandoned farmlands and regenerating clear-cut areas. Wintering habitat is moist tropical forest.

Diet: Primarily insects, but occasionally fruit.

Nesting and reproduction: Nesting activity in Tennessee does not begin until mid- to late May.

Clutch Size: Usually 3 to 4 eggs.

Incubation: The female incubates the eggs for 12 to 13 days.

Fledging: Both parents feed the young, which fledge 10 to 12 days.

Nest: The female builds the open cup-nest constructed of bark strips, weed stems, grasses, and plant down, and lined with fine grasses, hair or rootlets. It is usually placed in the crotch of a small tree or shrub. In Tennessee, nest heights range from 1 to 5 feet above the ground, with an average of 2.6 feet.

Status in Tennessee: The Chestnut-sided Warbler is a fairly common migrant across the state. In the mountains of East Tennessee it is a fairly common breeder. During spring migration, it is present from late April to mid-May, and during the fall from late August through mid-October. Breeding numbers in the state appear to be declining.

Dynamic map of Chestnut-sided Warbler eBird observations in Tennessee

Fun Facts:

• During the non-breeding season in Central America, the Chestnut-sided Warbler joins mixed-species flocks with other migrant and resident birds. It will often return to the same area and join the same flock in subsequent years.
• The song that has been described as sounding like please, please, pleased to mEEchew, is thought to be used to attract females and is heard before the females arrive and early in the nesting cycle.
• Recent DNA-based studies found that Chestnut-sided Warblers are closely related to Yellow Warblers and may explain why Chestnut-sided Warblers regularly sing songs nearly identical to those of the Yellow Warbler.
• The oldest known Chestnut-sided Warbler in the wild was 6 years, 11 months old.

Best places to see in Tennessee: In spring migration, Radnor Lake State Park and other forests and shrubby areas statewide. They can be found on Roan and Unaka Mountain in east Tennessee. Around Carver's Gap on Roan Mountain is an excellent place to find them in summer.

For more information:

Sources:

Nicholson, C. P. 1997. Atlas of Breeding Birds of Tennessee. Univ. of Tennessee Press, Knoxville.

Richardson, M. and D. W. Brauning. 1995. Chestnut-sided Warbler (Dendroica pensylvanica), The Birds of North America, No. 165 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D.C.

Robinson J. C. 1990. An Annotated Checklist of the Birds of Tennessee. Univ. of Tennessee Press, Knoxville.

Sibley, D. A. 2000. The Sibley Guide to Birds. A. A. Knopf, New York, NY.