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Species · Pennsylvania · BBS 2026 Release · 1966–2025

Hermit Thrush Population Trend in Pennsylvania

All statesForest birds

Hermit Thrush in Pennsylvania has surged: up 167% on the route-weighted index since 1968.

+167%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 →
81Routes 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 →
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 Hermit Thrush Trends in PennsylvaniaNotable 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 →

Hermit Thrush has surged in Pennsylvania: up 167% on the route-weighted index since 1968.

Hermit Thrush Population Forecast in Pennsylvania

If the recent trend holds, Hermit Thrush in Pennsylvania is projected to rise about 117% by 2030 — from 1.1 in 2025 to a central estimate of 2.4 (95% range 1.1–3.7). A 5-year backtest shows a typical error of ±139.8%, with 0% of held-out values landing inside the 95% band.

+117%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 →
2.4Projected 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 →
1.1–3.795% 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 →
±139.8%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, Hermit Thrush in Pennsylvania is projected to rise about 117% by 2030 — from 1.1 in 2025 to a central estimate of 2.4 (95% range 1.1–3.7). A 5-year backtest shows a typical error of ±139.8%, with 0% 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 →
20262.30.973.6
20272.30.993.6
20282.31.03.7
20292.41.03.7
20302.41.13.7

Hermit Thrush Survey Routes in Pennsylvania

Routes recording Hermit Thrush in Pennsylvania.
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 →
Odin1320251973
Marsh Hill1220251983
Rasselas1120221969
Cherry Sprs820251974
Ellenton820251982
Ansonia820252002
Lynch720251968
Little Marsh720241969
Starlight719991980
Russell City620251968
Lovelton620251999
Ridgway520181966
N Pine Grove420241969
Roulette420211972
Logue420251970
Susquehanna420241972
New Ringgold420081983
Sugar Grove420231995
Duboistown420211987
Sproul Sf-B420252002
Sigel320211991
Pocono Summit320251967
Canadensis320241977
Pocono Summit 2320102004
Mill Run320041999

Hermit Thrush Population Trend in Other States

alaskaarizonacaliforniacoloradoconnecticutidahoindianamainemarylandmassachusettsmichiganminnesotamontananevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooregonrhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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