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Worm-eating Warbler

Helmitheros vermivorus

Length: 5.5 inches Wingspan: 8.5 inches Seasonality: Migrant
ID Keys: Crisp black stripes on warm buffy head, plain brown body

Worm-eating Warbler - Helmitheros vermivorumThe Worm-eating Warbler is another poorly named bird, for they rarely if ever feed on earthworms, although they do feed heavily on caterpillars.  Relatively unusual for a warbler, they're often quite sluggish, slowly poking through the forest understory and the forest floor for insects. The female is extremely attached to her nest, and will often remain, motionless, until a predator (or curious bird watcher) is within inches of the nest.  The mother will then burst from the nest, feigning injury a short distance away to try and lure the intruder away from the nest.  Their dry trilling is very reminiscent of the Chipping Sparrow's song.

Habitat: Found in deciduous forests during the summer breeding season, especially slopes or shaded banks with a thick undergrowth of shrubs and saplings.  Found in dense thickets or forest undergrowth during migration and in winter.

Diet: Primarily feeds on caterpillars and other insects, as well as spiders and occasionally snails.

Behavior: Forages in trees and shrubs for insects, especially on the bark of tree trunks and branches.  Will also forage on the ground, probing fallen leaves for insects.  Often a relatively sluggish forager, at least compared to most warblers.

Breeding: Non-breeder in South Dakota.

Song: Flat one-note insect-like trilling.  Click here to listen to the Worm-eating Warbler's song.  Also, click to hear the Worm-eating Warbler's call.

Migration: Summers throughout much of the eastern United States wouth of the Great Lakes.  Winters in Mexico and southward.  

Interactive eBird map: Click here to access an interactive eBird map of Worm-eating Warbler sightings

Similar Species: Generally distinctive, although possibly confused with Swainson's Warbler.

Conservation Status: Have disappeared or sharply declined in some areas due to habitat loss.  Overall, numbers appear to currently be stable however.  The IUCN considers the Worm-eating Warbler to be a species of "Least Concern".

Further Information: 1) Patuxent Bird Identification InfoCenter, Worm-eating Warbler

2) WhatBird - Worm-eating Warbler

3) Audubon Guide - Worm-eating Warbler

Photo Information: Photo by Russ Wigh. Original presentation available here from Flickr.


Click on the map below for a higher-resolution view
Worm-eating Warbler - Range Map
South Dakota Status: Very rare migrant in the eastern part of the state.

Additional Worm-eating Warbler Photos (coming soon!)