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

Great Blue Heron Population Trend in Washington

All statesWetland birds

Great Blue Heron in Washington has declined: down 37% on the route-weighted index since 1970.

-37%Since 1970TrendPercent 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 →
83Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Great Blue Heron Trends in WashingtonNotable 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 Great Blue Heron in Washington. See the full index history below.

Great Blue Heron Population Forecast in Washington

If the recent trend holds, Great Blue Heron in Washington is projected to stay roughly flat through 2030, near 0.55 (95% range 0.01–1.1). A 5-year backtest shows a typical error of ±53%, with 100% of held-out values landing inside the 95% band.

-2%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 →
0.55Projected 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 →
0.01–1.195% 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 →
±53%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, Great Blue Heron in Washington is projected to stay roughly flat through 2030, near 0.55 (95% range 0.01–1.1). A 5-year backtest shows a typical error of ±53%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20260.580.051.1
20270.580.041.1
20280.570.031.1
20290.560.021.1
20300.550.011.1

Great Blue Heron Survey Routes in Washington

Routes recording Great Blue Heron in Washington.
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 →
Ilwaco1620251975
Othello619911983
Issaquah319841970
Reardan320211968
Odessa320232000
Yakima320251993
Scootney Reservoir320252009
Hanford Site319961988
Port Angeles220241970
Moses Lake220211973
Camas220091977
Snowden220221983
Ewan220191983
Spring Lake220222015
Curlew220051999
Malden220241998
Harwood219971995
Bay View220171993
Carnation220241989
Ewan 2220242023
Columbia Nwr220221992
Turnbull Nwr220231993
Vashon Is.220251995
Horn Rapids220242005
Ozette120241975

Great Blue Heron Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

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