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

Snowy Egret Population Trend in Colorado

All statesWetland birds

Snowy Egret in Colorado has fallen sharply: down 65% on the route-weighted index since 1991.

-65%Since 1991TrendPercent 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 →
9Routes 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 →
30YearsYears 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 ColoradoNotable 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 declinecomputed 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 fallen sharply in Colorado: down 65% on the route-weighted index since 1991.

Snowy Egret Population Forecast in Colorado

If the recent trend holds, Snowy Egret in Colorado is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.15). A 5-year backtest shows a typical error of ±66.1%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.01Projected 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 →
0.00–0.1595% 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 →
±66.1%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 Colorado is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.15). A 5-year backtest shows a typical error of ±66.1%, with 100% of held-out values landing inside the 95% band.19782029
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 →
20250.020.000.16
20260.010.000.15
20270.010.000.15
20280.010.000.15
20290.010.000.15

Snowy Egret Survey Routes in Colorado

Routes recording Snowy Egret in Colorado.
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 →
Arsenal320142003
Hudson120161994
Arsenal 2120242021
Guffey120232023
De Beque120012001
Moffat119781978
Alamosa120241989
Cortez119951993
Angora120012001

Snowy Egret Population Trend in Other States

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

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