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Species · Pennsylvania · BBS 2025 Release · 1966–2024

Blue-winged Warbler Population Trend in Pennsylvania

All statesForest birds

Blue-winged Warbler in Pennsylvania has held roughly steady: down 9% on the route-weighted index since 1968.

-9%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 →
101Routes 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 →
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 Blue-winged 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 Blue-winged Warbler in Pennsylvania. See the full index history below.

Blue-winged Warbler Population Forecast in Pennsylvania

If the recent trend holds, Blue-winged Warbler in Pennsylvania is projected to rise about 145% by 2029 — from 0.16 in 2024 to a central estimate of 0.38 (95% range 0.00–0.90). A 5-year backtest shows a typical error of ±191.2%, with 100% of held-out values landing inside the 95% band.

+145%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 →
0.38Projected 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 →
0.00–0.9095% 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 →
±191.2%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, Blue-winged Warbler in Pennsylvania is projected to rise about 145% by 2029 — from 0.16 in 2024 to a central estimate of 0.38 (95% range 0.00–0.90). A 5-year backtest shows a typical error of ±191.2%, 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 →
20250.390.000.90
20260.390.000.90
20270.390.000.90
20280.390.000.90
20290.380.000.90

Blue-winged Warbler Survey Routes in Pennsylvania

Routes recording Blue-winged 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 →
Jacobus1419971992
Duvall520211975
Harmonsburg420231968
Eldred320221987
Poyntelle320241975
West Grove319961975
Espyville220091967
Ferris Crnrs220241971
Waller220141978
Starlight219991975
Canadensis220141992
Portersville219751974
Brunnerville220071969
Quakertown219871970
Starlight 2220242008
Slippery Rk119941970
Clover120241988
Whig Hill120091966
Akeley119791968
Teepleville120241967
Sigel120141990
N Washington120221967
N Pine Grove120121969
Betula120221987
Russell City120122012

Blue-winged Warbler Population Trend in Other States

alabamaarkansasconnecticutdelawaregeorgiaillinoisindianaiowakentuckymarylandmassachusettsmichiganminnesotamississippimissourinew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomarhode-islandtennesseevermontvirginiawest-virginiawisconsin

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