Worm-eating Warbler

The Worm-eating Warbler is a plain but distinctively marked bird, with warm buffy-olive underparts and a buffy head set off by two bold black stripes running along the crown and through the eye. Its upperparts are a plain, unstreaked olive-brown, and it has a notably long, pointed bill relative to its body size.

Despite the name, this species does not eat earthworms; the name instead refers to its habit of feeding on caterpillars, often colloquially called "worms," which it extracts by probing into curled dead leaves.

Key field marks

• Buffy head with two bold black stripes (crown stripe and eye stripe)
• Plain, unstreaked olive-brown upperparts and buffy-olive underparts
• Long, pointed bill
• Pinkish legs
• No wingbars

Similar species

Swainson's Warbler is superficially similar in its plain brown coloring but lacks the bold black head stripes of Worm-eating Warbler and has a plainer face with just a dark eyeline. Sparrows with striped crowns are much bulkier and lack the thin warbler bill and olive tones.

Worm-eating Warblers breed in mature deciduous forest across the eastern United States, with a strong preference for steep, wooded hillsides and ravines that have a dense shrub layer, often in areas with mountain laurel or similar understory thickets.

They winter in the understory of humid lowland forest from Mexico through Central America and into the Caribbean.

Behavior and voice

Worm-eating Warblers forage in a very distinctive way, often hanging upside down or clinging to probe into clusters of curled dead leaves in search of hidden caterpillars, a technique that sets them apart from most other warblers.

The song is a dry, insect-like trill delivered on a single pitch, similar to the trill of a Chipping Sparrow but more buzzy and less musical.

Nesting

The nest is built on the ground, typically on a steep, wooded slope, tucked among dead leaves at the base of a shrub or sapling. Clutches usually contain 3-5 eggs.