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Species · Pennsylvania · BBS 2025 Release · 1966–2024

Nashville Warbler Population Trend in Pennsylvania

All statesForest birds

Nashville Warbler in Pennsylvania has fallen sharply: down 68% on the route-weighted index since 1969.

-68%Since 1969TrendPercent 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 →
40Routes 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 →
52YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Nashville Warbler 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 →

No notable trend signals for Nashville Warbler in Pennsylvania. See the full index history below.

Nashville Warbler Population Forecast in Pennsylvania

If the recent trend holds, Nashville Warbler in Pennsylvania is projected to stay roughly flat through 2029, near 0.03 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±112.7%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.03Projected 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 →
0.00–0.0895% 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 →
±112.7%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, Nashville Warbler in Pennsylvania is projected to stay roughly flat through 2029, near 0.03 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±112.7%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.030.000.08
20260.030.000.08
20270.030.000.08
20280.030.000.08
20290.030.000.08

Nashville Warbler Survey Routes in Pennsylvania

Routes recording Nashville Warbler 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 →
Arnot219961996
Clover119881988
Ellenton120221988
Wyalusing120101989
Whig Hill120102010
Teepleville119931971
Rothrock Sf120122012
Lynch120231993
Lovelton120191999
N Pine Grove120162003
Pottersdale119951975
Starlight 2120192008
Betula120052001
Ansonia120022002
Sproul Sf-A120062003
Rasselas120041976
Roulette119891989
Cherry Sprs120101977
Mawr Glen119941982
Austinville119871987
Rush119941970
Bow Bridge119851969
Marsh Hill120241983
Pocono Summit120191967
Hop Bottom120061969

Nashville Warbler Population Trend in Other States

californiaconnecticutidahomainemarylandmassachusettsmichiganminnesotamontananew-hampshirenew-jerseynew-yorknorth-dakotaoregonrhode-islandvermontvirginiawashingtonwest-virginiawisconsin

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