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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 vermivorum

The 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".

Photo Information

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

Further Information