BirdAnalyst
Species · Pennsylvania · BBS 2026 Release · 1966–2025

Green Heron Population Trend in Pennsylvania

All statesWetland birds

Green Heron in Pennsylvania has declined: down 48% on the route-weighted index since 1968.

-48%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 →
123Routes 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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Green Heron 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 Green Heron in Pennsylvania. See the full index history below.

Green Heron Population Forecast in Pennsylvania

If the recent trend holds, Green Heron in Pennsylvania is projected to fall about 38% by 2030 — from 0.30 in 2025 to a central estimate of 0.19 (95% range 0.03–0.35). A 5-year backtest shows a typical error of ±23.2%, with 100% of held-out values landing inside the 95% band.

-38%Change by 2030TrendPercent 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 →
0.19Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.03–0.3595% 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 →
±23.2%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, Green Heron in Pennsylvania is projected to fall about 38% by 2030 — from 0.30 in 2025 to a central estimate of 0.19 (95% range 0.03–0.35). A 5-year backtest shows a typical error of ±23.2%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20260.210.050.37
20270.200.040.36
20280.200.040.36
20290.190.030.35
20300.190.030.35

Green Heron Survey Routes in Pennsylvania

Routes recording Green Heron 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 →
Eldred420151975
Drehersville 2420242001
Ferris Crnrs320251971
Rush320251971
Hop Bottom320251967
Honesdale320241972
Parkwood320191979
Brunnerville320071969
Schaefferstown 2320182002
Shrewsbury320121991
Slippery Rk219921971
N Pine Grove220221971
Betula220161975
Russell City219721972
Ridgway220182008
Bow Bridge220251969
Millville220251977
Starlight219881970
Greentown220191969
Poyntelle220241979
Portersville219761973
Beaver220231972
Kaylor220181969
Clear Spring220131968
Mifflintown220251970

Green Heron Population Trend in Other States

alabamaarizonaarkansascaliforniaconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonrhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawashingtonwest-virginiawisconsin

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.