Worm-eating Warbler
Worm-eating Warbler has surged: up 104% on the route-weighted index since 1968.
About the Worm-eating Warbler
The Worm-eating Warbler (Helmitheros vermivorum) is a North American member of the Wood-Warblers (Parulidae). In this analysis it is grouped with the forest birds.
- Size
- 4.5–5.5 in long (11–14 cm) — a small, active songbird (typical for the family)
- Habitat
- Woodlands and forest edges, including wooded suburbs and parks.
- Diet
- Insects and spiders gleaned from foliage and bark, with seeds and berries in season.
- Range
- Recorded on 797 Breeding Bird Survey routes across 28 states, most concentrated in the Appalachian Mountains.
- Family
- Parulidae · Forest birds
Notable Worm-eating Warbler TrendsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →
Worm-eating Warbler has surged in surveyed states: up 104% on the route-weighted index since 1968.
Worm-eating Warbler Population Forecast
If the recent trend holds, Worm-eating Warbler is projected to rise about 37% by 2029 — from 0.18 in 2024 to a central estimate of 0.25 (95% range 0.18–0.32). A 5-year backtest shows a typical error of ±23.5%, with 80% of held-out values landing inside the 95% band.
Where the Worm-eating Warbler Is Detected
BBS routes recording Worm-eating Warbler, sized by most recent count.
Worm-eating Warbler Population Trend by State
Worm-eating Warbler Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
Worm-eating Warbler Conservation Status
Our route-weighted index shows it up about 104% since 1968.
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.