Worm-eating Warbler

Helmitheros vermivorum

Order PASSERIFORMES - Family PARULIDAE

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1. Cool Facts
2. Description
3. Similar Species
4. Sound
5. Range
6. Habitat
7. Food
8. Behavior
9. Reproduction
10. Conservation Status
11. Other Names

A small, drab, but elegantly marked bird of the eastern deciduous forests, the Worm-eating Warbler is often found on steep slopes with dense understory. True to its name, it feeds largely on caterpillars ("worms").

Cool Facts

• Late in incubation the female Worm-eating Warbler sits so tight on her nest that only touching her will flush her. Her cryptic coloring makes immobility a safe strategy. If she is flushed, she will flutter across the ground with her wings and tail spread, acting helpless to lure predators away from the nest.

• Young Worm-eating Warblers typically leave their nest 8-10 days after hatching. Chicks as young as five days old have been observed leaving the nest and surviving, although they cannot fly at that age.

• Although the Worm-eating Warbler forages in the understory near the ground and nests on the ground, it does not spend much time on the forest floor. It does not forage there, and when on the ground it hops instead of walking.

Description

• Size: 11-13 cm (4-5 in)
• Weight: 12-14 g (0.42-0.49 ounces)

• Small songbird.
• Head and underparts buffy.
• Black crown stripes and stripe through eye.

• Upperparts olive green.
• No wingbars or tail spots.
• Relatively long pointed bill, dark above and pink below.
• Short, square tail.

Sex Differences

Sexes alike.

Immature

Immature like adult.

Similar Species

• Swainson's Warbler has brown cap and indistinct eyestripe, and is colored in mostly browns, not the distinctive olive and buffy of a Worm-eating Warbler.

Sound

Song a rapid, dry trill, often insect-like.

»listen to songs of this species

Range

Summer Range

Breeds locally in the Appalachian region, and westward to Missouri and eastern Texas, southward to northwestern Florida.

Winter Range

Winters in Central America and in Caribbean.

Habitat

• Breeds in mature deciduous or mixed deciduous-coniferous forest with patches of dense understory, usually on steep hillside.
• Winters in tropical forests.

Food

Arthropods, spiders, slugs, and especially caterpillars.

Behavior

Foraging

Gleans in low shrubs, but only rarely on ground. Probes into hanging dead leaf clusters and foliage.

Reproduction

Nest Type

Nest a cup of skeletonized leaves lined with moss, placed on ground.

Egg Description

White to pink, with brown speckles.

Clutch Size

3-6 eggs.

Condition at Hatching

Helpless and naked.

Conservation Status

Dependence on large forests for nesting make it vulnerable to population decreases. Populations seem stable across United States. Listed on the Audubon Watchlist.

Other Names

Paruline vermivore (French)
Chipe gusanero (Spanish)

Sources used to construct this page:

Hanners, L. A., and S. R. Patton. 1998. Worm-eating Warbler (Helmitheros vermivorus). In The Birds of North America, No. 367 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.