BirdAnalyst
Species · BCR 28 · BBS 2025 Release · 1966–2024

Worm-eating Warbler In Appalachian Mountains

All regionsAppalachian MountainsForest birds

Worm-eating Warbler in Appalachian Mountains has surged: up 213% on the route-weighted index since 1968.

+213%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 →
58YearsYears 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 213% 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 36% by 2029 — from 1.1 in 2024 to a central estimate of 1.6 (95% range 1.1–2.0). A 5-year backtest shows a typical error of ±29.4%, with 100% of held-out values landing inside the 95% band.

+36%Change by 2029TrendPercent 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 →
1.6Projected 2029 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 →
±29.4%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 36% by 2029 — from 1.1 in 2024 to a central estimate of 1.6 (95% range 1.1–2.0). A 5-year backtest shows a typical error of ±29.4%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20251.50.982.0
20261.51.02.0
20271.51.02.0
20281.51.02.0
20291.61.12.0

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 →
Piney GroveMARYLAND212024
OldtownMARYLAND182024
BattlecreekSOUTH-CAROLINA152014
Cumberlnd GpKENTUCKY132018
FontanaNORTH-CAROLINA132024
Front RoyalVIRGINIA122024
Tar HollowOHIO92024
ShanghaiWEST-VIRGINIA92022
Shawnee S.F. 2OHIO82019
St CollegePENNSYLVANIA82024
McfarlandTENNESSEE81993
MeccaTENNESSEE82023
Gr North MtnVIRGINIA82024
GlenwoodVIRGINIA82023
Shenandoa NpVIRGINIA82022
Beattyville 2KENTUCKY72024
HarbuckTENNESSEE72023
W AugustaVIRGINIA72024
Bald KnobVIRGINIA72024
DouthatVIRGINIA72012
Green RidgeMARYLAND62024
Table RockNORTH-CAROLINA62022
StoneybreakPENNSYLVANIA62024
Tussey Mtn.PENNSYLVANIA62024
MarionVIRGINIA61982

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.