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

Great Blue Heron Population Trend in Pennsylvania

All statesWetland birds

Great Blue Heron in Pennsylvania has surged: up 343% on the route-weighted index since 1968.

+343%Since 1968
124Routes In State
58Years

Notable Great Blue Heron Trends in Pennsylvania

long arc increasecomputed index

Great Blue Heron has surged in Pennsylvania: up 343% on the route-weighted index since 1968.

Great Blue Heron Population Forecast in Pennsylvania

If the recent trend holds, Great Blue Heron in Pennsylvania is projected to rise about 58% by 2029 — from 0.67 in 2024 to a central estimate of 1.1 (95% range 0.75–1.4). A 5-year backtest shows a typical error of ±38.4%, with 40% of held-out values landing inside the 95% band.

+58%Change by 2029
1.1Projected 2029 index
0.75–1.495% range
±38.4%Backtest error
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 index95% low95% high
20251.00.691.3
20261.00.711.3
20271.00.721.4
20281.10.731.4
20291.10.751.4

Great Blue Heron Survey Routes in Pennsylvania

Routes recording Great Blue Heron in Pennsylvania.
Beaver520231984
Teepleville420241967
Plesant Grov420221969
Drehersville419981986
Akron419971997
Mt Gretna 2420182001
Drehersville 2420242001
Shrewsbury420191991
N Washington320221973
Canadensis320241998
Parkwood320241998
Mifflintown320231980
Brunnerville320091974
Brunnerville 2320242010
Bendersville320241993
Slippery Rk219941970
Clover220241988
Akeley219731966
Arnot220241972
Logue220221980
English Ctr219731968
Rush220241970
Susquehanna220241972
Duvall220211982
Kaylor220231997

Great Blue Heron Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonrhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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