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Species · Pennsylvania · BBS 2025 Release · 1966–2024

Louisiana Waterthrush Population Trend in Pennsylvania

All statesForest birds

Louisiana Waterthrush in Pennsylvania has surged: up 364% on the route-weighted index since 1968.

+364%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 →
95Routes 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 Louisiana Waterthrush 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 →

Louisiana Waterthrush has surged in Pennsylvania: up 364% on the route-weighted index since 1968.

Louisiana Waterthrush Population Forecast in Pennsylvania

If the recent trend holds, Louisiana Waterthrush in Pennsylvania is projected to stay roughly flat through 2029, near 0.64 (95% range 0.41–0.86). A 5-year backtest shows a typical error of ±18.2%, with 100% of held-out values landing inside the 95% band.

+5%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 →
0.64Projected 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 →
0.41–0.8695% 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 →
±18.2%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, Louisiana Waterthrush in Pennsylvania is projected to stay roughly flat through 2029, near 0.64 (95% range 0.41–0.86). A 5-year backtest shows a typical error of ±18.2%, 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 →
20250.610.380.84
20260.620.390.84
20270.620.400.85
20280.630.400.86
20290.640.410.86

Louisiana Waterthrush Survey Routes in Pennsylvania

Routes recording Louisiana Waterthrush 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 →
Laurel Hill620241978
Ravensburg519751966
Beaver420241990
Duboistown420241991
Canadensis320231985
Poyntelle320241973
Landisburg320241978
Roulette219811976
Logue219881976
Mawr Glen220241982
Bow Bridge220131969
Waller220231997
Hop Bottom220241967
Susquehanna220241978
Rector219771966
Martinsburg220241992
Bald Eagle220221978
Doubling Gap219661966
Peru Mills220241968
Naginey220241977
Warrens Mill220241971
Ltl Pine Cr220241990
Mill Run220231980
Berwick220221985
Tussey Mtn.220241993

Louisiana Waterthrush Population Trend in Other States

alabamaarkansasconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomarhode-islandsouth-carolinatennesseetexasvermontvirginiawest-virginiawisconsin

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