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

Osprey Population Trend in Pennsylvania

All statesGeneralists

Osprey in Pennsylvania has surged: up 481% on the route-weighted index since 1975.

+481%Since 1975TrendPercent 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 →
36Routes 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 →
35YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Osprey 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 →

Osprey has surged in Pennsylvania: up 481% on the route-weighted index since 1975.

Osprey Population Forecast in Pennsylvania

If the recent trend holds, Osprey in Pennsylvania is projected to rise about 24% by 2029 — from 0.09 in 2024 to a central estimate of 0.11 (95% range 0.06–0.16). A 5-year backtest shows a typical error of ±20.4%, with 100% of held-out values landing inside the 95% band.

+24%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 →
0.11Projected 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 →
0.06–0.1695% 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 →
±20.4%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, Osprey in Pennsylvania is projected to rise about 24% by 2029 — from 0.09 in 2024 to a central estimate of 0.11 (95% range 0.06–0.16). A 5-year backtest shows a typical error of ±20.4%, with 100% of held-out values landing inside the 95% band.19702029
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 →
20250.100.060.15
20260.110.060.15
20270.110.060.16
20280.110.060.16
20290.110.060.16

Osprey Survey Routes in Pennsylvania

Routes recording Osprey 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 →
Espyville220242012
Betula220222022
Russell City220232001
Mars220232009
Pocono Summit220221993
Greentown220112001
Mount Joy220242019
Berwick120122001
Wild Creek120011989
Pocono Summit 2120042004
Starlight 2120182018
Pottersdale120242001
Rasselas120212016
Roulette120172017
Little Marsh120231995
Rosecrans120242024
English Ctr119701970
Ravensburg119701970
Waller119981998
Landisburg120142003
Canadensis120242018
Poyntelle119861986
Beaver120242019
Brunnerville 2120212021
Schaefferstown 2120222011

Osprey Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooregonrhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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