BirdAnalyst
Species · Pennsylvania · BBS 2025 Release · 1966–2024

Bald Eagle Population Trend in Pennsylvania

All statesGeneralists

Bald Eagle in Pennsylvania has surged: up 618% on the route-weighted index since 1983.

+618%Since 1983TrendPercent 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 →
61Routes 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 →
34YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Bald Eagle 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 →

Bald Eagle has surged in Pennsylvania: up 618% on the route-weighted index since 1983.

Bald Eagle Population Forecast in Pennsylvania

If the recent trend holds, Bald Eagle in Pennsylvania is projected to fall about 52% by 2029 — from 0.32 in 2024 to a central estimate of 0.15 (95% range 0.05–0.25). A 5-year backtest shows a typical error of ±54%, with 20% of held-out values landing inside the 95% band.

-52%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 →
0.15Projected 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 →
0.05–0.2595% 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 →
±54%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, Bald Eagle in Pennsylvania is projected to fall about 52% by 2029 — from 0.32 in 2024 to a central estimate of 0.15 (95% range 0.05–0.25). A 5-year backtest shows a typical error of ±54%, with 20% of held-out values landing inside the 95% band.19772029
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 →
20250.140.040.24
20260.140.040.24
20270.140.050.24
20280.150.050.25
20290.150.050.25

Bald Eagle Survey Routes in Pennsylvania

Routes recording Bald Eagle 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 →
Arnot420242018
Waterstreet420242013
Brunnerville 2320242024
Jacobus320242024
Harmonsburg220222010
Wyalusing220231998
Pottersdale220232023
Rasselas220072007
Little Marsh220152015
Pocono Summit220232011
Elizabethvil220212001
Margaret220242024
Espyville120241994
Clover120232000
Ferris Crnrs120232006
Whig Hill120212010
Ellenton120192019
Teepleville120222017
Lynch120172014
Berwick120232023
Wild Creek120212021
Odin120242024
Lovelton120232021
Ansonia120132006
Mars120242010

Bald Eagle Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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