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

Great Blue Heron Population Trend in Arizona

All statesWetland birds

Great Blue Heron in Arizona has surged: up 241% on the route-weighted index since 1975.

+241%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 →
40Routes 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 →
48YearsYears 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 ArizonaNotable 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 →

Great Blue Heron has surged in Arizona: up 241% on the route-weighted index since 1975.

Great Blue Heron Population Forecast in Arizona

If the recent trend holds, Great Blue Heron in Arizona is projected to rise about 33% by 2029 — from 0.34 in 2024 to a central estimate of 0.46 (95% range 0.00–1.9). A 5-year backtest shows a typical error of ±251.5%, with 100% of held-out values landing inside the 95% band.

+33%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 →
0.46Projected 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 →
0.00–1.995% 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 →
±251.5%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 Arizona is projected to rise about 33% by 2029 — from 0.34 in 2024 to a central estimate of 0.46 (95% range 0.00–1.9). A 5-year backtest shows a typical error of ±251.5%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.460.001.9
20260.460.001.9
20270.460.001.9
20280.460.001.9
20290.460.001.9

Great Blue Heron Survey Routes in Arizona

Routes recording Great Blue Heron in Arizona.
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 →
Palo Verde 21020242014
Palo Verde620131994
Patagonia420171975
Alamo Res.320162015
Cutter320141993
Prescott220161978
Cutter 2220182015
Tonto Vill.220212006
Bartlett Res220222022
Happy Jack220221999
Sprucedale219981998
Black Mesa119921992
New River120001992
Florence119701970
Laguna120231968
Coolidge119771977
Pomerene120241977
San Simon119841982
Peña Blanca120051994
Riviera120232023
Williams120181993
Maine120112008
Skull Valley120241999
Forest Lakes120222022
Pinetop120042004

Great Blue Heron Population Trend in Other States

alabamaalaskaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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