Guide to North American Birds
Conservation status Local breeding populations rise and fall, apparently in response to outbreaks of certain forest insects, such as spruce budworm. Overall numbers of this warbler seem healthy.
Family Wood Warblers
Habitat Deciduous and mixed forests; in migration, groves, brush. Breeds in bogs, swamps, and forests. Prefers openings in second growth balsam-tamarack bogs, or aspen and pine woods, or edges of dense spruce forest. Nests near slight depressions of boggy ground. During spring migration, mostly high in trees. During fall migration, often lower in saplings, brush, weedy fields.
This bird is found in Tennessee only briefly, during spring and fall migration; but there is no point in giving it a more descriptive name, because the bird itself is nondescript. The male makes up for his plain appearance with a strident staccato song, surprisingly loud for the size of the bird. Nesting in northern forests, the Tennessee Warbler goes through population cycles: it often becomes very numerous during population explosions of the spruce budworm, a favored food.

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Feeding Behavior

Forages in the outer foliage of trees, sometimes hanging head downward. Takes insects in dense patches of weeds. In summer, male may feed mostly in treetops, female remaining nearer the ground. Forages in flocks of up to 200 on wintering grounds, often in coffee plantations.


Eggs

5-6, sometimes 4-7. May lay more eggs during outbreaks of spruce budworm. Eggs white, with some marks of brown or purple. Rarely parasitized by cowbirds. Incubation by female only, 11-12 days. Young: Development and care of the young, and age when they leave the nest, are not well known. Probably 1 brood per year.


Young

Development and care of the young, and age when they leave the nest, are not well known. Probably 1 brood per year.

Diet

Mostly insects, some berries and nectar. In summer feeds mainly on insects, including caterpillars, scale insects, aphids, beetles, flies, ants, leafhoppers, and others; also spiders. Takes nectar from catkins, and some juice from grapes. In winter in the tropics, feeds on nectar, berries, and the protein-rich structures that cecropia trees produce at base of leaves.


Nesting

Male has loud repetitious song on breeding territory. In ideal habitat, nests are closely spaced in loose colonies. During courtship, male performs song flight up to 60' above the ground. Nest: Concealed in a depression on ground under bushes or overhanging grass. Site is usually on mossy hummock in a wet area, but will nest on fairly dry ground on steep hillsides. Nest (built by female) is open cup made of thin grass stems; lined with fine dry grass, porcupine quills, or moose hair.

Illustration © David Allen Sibley.
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Text © Kenn Kaufman, adapted from
Lives of North American Birds

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Migration

In spring, many migrate north across the western part of the Gulf of Mexico. Strays show up regularly in the west, especially along the Pacific Coast in fall, where a few may spend the winter.

  • 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.

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Songs and Calls

A sharp, staccato di-dit-di-dit-swit-swit-swit-chip-chip-chip-chip-chip, fastest at the end; song often comprised of 3 distinct parts.
Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
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