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Species · Indiana · BBS 2026 Release · 1966–2025

Worm-eating Warbler Population Trend in Indiana

All statesForest birds

Worm-eating Warbler in Indiana has surged: up 201% on the route-weighted index since 1973.

+201%Since 1973TrendPercent 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 →
12Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
50YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Worm-eating Warbler Trends in IndianaNotable 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 Indiana: up 201% on the route-weighted index since 1973.

Worm-eating Warbler Population Forecast in Indiana

If the recent trend holds, Worm-eating Warbler in Indiana is projected to rise about 26% by 2030 — from 0.28 in 2025 to a central estimate of 0.36 (95% range 0.03–0.68). A 5-year backtest shows a typical error of ±251.5%, with 60% of held-out values landing inside the 95% band.

+26%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 →
0.36Projected 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 →
0.03–0.6895% 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 →
±251.5%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 Indiana is projected to rise about 26% by 2030 — from 0.28 in 2025 to a central estimate of 0.36 (95% range 0.03–0.68). A 5-year backtest shows a typical error of ±251.5%, with 60% of held-out values landing inside the 95% band.19682030
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 →
20260.340.010.67
20270.340.020.67
20280.350.020.68
20290.350.020.68
20300.360.030.68

Worm-eating Warbler Survey Routes in Indiana

Routes recording Worm-eating Warbler in Indiana.
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 →
Hoosier1220251990
Celestine220191980
Cumback119971968
Indian Spgs120152009
Clear Spring120231982
New Phila120191989
Corydon120251972
Vevay119961996
Kokomo120192019
Belmont120231983
Georgia120181999
Cross Plains120222022

Worm-eating Warbler Population Trend in Other States

alabamaarkansasconnecticutdelawaregeorgiaillinoisiowakentuckylouisianamarylandmassachusettsmississippimissourinew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvirginiawest-virginiawisconsin

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