BirdAnalyst
Species · BCR 28 · BBS 2026 Release · 1966–2025

Worm-eating Warbler In Appalachian Mountains

All regionsAppalachian MountainsForest birds

Worm-eating Warbler in Appalachian Mountains has surged: up 206% on the route-weighted index since 1968.

+206%Since 1968TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
310Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Worm-eating Warbler has surged in Appalachian Mountains: up 206% on the route-weighted index since 1968.

Worm-eating Warbler In Appalachian Mountains Population Forecast

If the recent trend holds, Worm-eating Warbler in Appalachian Mountains is projected to rise about 39% by 2030 — from 1.1 in 2025 to a central estimate of 1.5 (95% range 1.1–2.0). A 5-year backtest shows a typical error of ±32.7%, with 100% of held-out values landing inside the 95% band.

+39%Change by 2030TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
1.5Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
1.1–2.095% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±32.7%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Worm-eating Warbler in Appalachian Mountains is projected to rise about 39% by 2030 — from 1.1 in 2025 to a central estimate of 1.5 (95% range 1.1–2.0). A 5-year backtest shows a typical error of ±32.7%, with 100% of held-out values landing inside the 95% band.19662030
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20261.50.972.0
20271.50.992.0
20281.51.02.0
20291.51.02.0
20301.51.12.0

Routes In Appalachian Mountains

Routes recording Worm-eating Warbler in Appalachian Mountains.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
OldtownMARYLAND232025
Piney GroveMARYLAND162025
BattlecreekSOUTH-CAROLINA152014
Cumberlnd GpKENTUCKY132018
HixWEST-VIRGINIA122025
Front RoyalVIRGINIA112025
Tar HollowOHIO92024
CovingtonVIRGINIA92025
Green RidgeMARYLAND82025
Shawnee S.F. 2OHIO82019
NagineyPENNSYLVANIA82025
Tussey Mtn.PENNSYLVANIA82025
McfarlandTENNESSEE81993
MeccaTENNESSEE82023
Gr North MtnVIRGINIA82025
GlenwoodVIRGINIA82023
Shenandoa NpVIRGINIA82022
Beattyville 2KENTUCKY72024
HarbuckTENNESSEE72023
DouthatVIRGINIA72012
Table RockNORTH-CAROLINA62022
Wayne N.F.OHIO62025
Zaleski S.F.OHIO62025
MarionVIRGINIA61982
Rural RetrtVIRGINIA62025

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.