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

Great Egret Population Trend in California

All statesWetland birds

Great Egret in California has surged: up 43× on the route-weighted index since 1971.

43×Since 1971TrendPercent 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 →
81Routes 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 →
55YearsYears 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 Egret Trends in CaliforniaNotable 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 Egret has surged in California: up 43× on the route-weighted index since 1971.

Great Egret Population Forecast in California

If the recent trend holds, Great Egret in California is projected to rise about 66% by 2029 — from 1.3 in 2024 to a central estimate of 2.1 (95% range 0.76–3.4). A 5-year backtest shows a typical error of ±78.6%, with 80% of held-out values landing inside the 95% band.

+66%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 →
2.1Projected 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 →
0.76–3.495% 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 →
±78.6%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 Egret in California is projected to rise about 66% by 2029 — from 1.3 in 2024 to a central estimate of 2.1 (95% range 0.76–3.4). A 5-year backtest shows a typical error of ±78.6%, with 80% 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 →
20252.00.693.3
20262.00.713.3
20272.00.733.4
20282.10.753.4
20292.10.763.4

Great Egret Survey Routes in California

Routes recording Great Egret in California.
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 →
Dorris4420191973
Glenn2820231971
Hughson1720241968
Likely1420241984
Staten Is.1420241994
Brawley1320121984
Niland1120241973
Atwater1120121982
Collegeville 21120232007
Ora Loma1020241972
Fairfax820241972
Westley820241975
Honey Lake820191987
Buena Vista820191995
Zamora720241982
Athlone720072003
Sisquoc620002000
Tranquillity620231972
Pennington520241978
Palo Verde520241973
Jofegan 2420242024
Orland420191984
Havasu Lake419731973
Clear Lk Res419991984
Tracy 2420152015

Great Egret Population Trend in Other States

alabamaarizonaarkansascoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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