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Species · California · BBS 2025 Release · 1966–2024

Snowy Egret Population Trend in California

All statesWetland birds

Snowy Egret in California has surged: up 95% on the route-weighted index since 1973.

+95%Since 1973TrendPercent 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 →
47Routes 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 →
53YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Snowy 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 →

Snowy Egret has surged in California: up 95% on the route-weighted index since 1973.

Snowy Egret Population Forecast in California

If the recent trend holds, Snowy Egret in California is projected to rise about 220% by 2029 — from 0.19 in 2024 to a central estimate of 0.62 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±136.7%, with 100% of held-out values landing inside the 95% band.

+220%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 →
0.62Projected 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 →
0.00–1.395% 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 →
±136.7%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, Snowy Egret in California is projected to rise about 220% by 2029 — from 0.19 in 2024 to a central estimate of 0.62 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±136.7%, with 100% of held-out values landing inside the 95% band.19712029
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 →
20250.610.001.3
20260.610.001.3
20270.610.001.3
20280.620.001.3
20290.620.001.3

Snowy Egret Survey Routes in California

Routes recording Snowy 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 →
Riovista1920071994
Glenn1720221975
Dorris1320191972
Fairfax1020241972
Westley920211977
Cima619771977
Hughson520182018
Palo Verde520031976
Cp. Pendleton420042004
Brawley320101975
Harbor Lake 2320222014
Staten Is.320242002
Crowley Lake220191972
Clear Lk Res219841984
Zamora220232003
Coyote220241994
El Toro219961996
Nubieber119891989
Crescent Cty120241996
Ventucopa119801980
Hullville120072007
Pennington120221971
Arvin120221982
Atwater120121982
Oroville120061980

Snowy Egret Population Trend in Other States

alabamaarizonaarkansascoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianakansaslouisianamainemarylandmassachusettsmississippimissourinebraskanevadanew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaoklahomaoregonrhode-islandsouth-carolinasouth-dakotatennesseetexasutahvirginiawisconsinwyoming

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