BirdAnalyst
Species · South Dakota · BBS 2025 Release · 1966–2024

Great Egret Population Trend in South Dakota

All statesWetland birds

Great Egret in South Dakota has risen sharply: up 73% on the route-weighted index since 1989.

+73%Since 1989TrendPercent 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 →
15Routes 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 →
33YearsYears 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 South DakotaNotable 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 risen sharply in South Dakota: up 73% on the route-weighted index since 1989.

Great Egret Population Forecast in South Dakota

If the recent trend holds, Great Egret in South Dakota is projected to rise about 90% by 2028 — from 0.13 in 2023 to a central estimate of 0.25 (95% range 0.00–0.83). A 5-year backtest shows a typical error of ±184.5%, with 100% of held-out values landing inside the 95% band.

+90%Change by 2028TrendPercent 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 →
0.25Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.8395% 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 →
±184.5%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 Egret in South Dakota is projected to rise about 90% by 2028 — from 0.13 in 2023 to a central estimate of 0.25 (95% range 0.00–0.83). A 5-year backtest shows a typical error of ±184.5%, with 100% of held-out values landing inside the 95% band.19862028
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 →
20240.250.000.83
20250.250.000.83
20260.250.000.83
20270.250.000.83
20280.250.000.83

Great Egret Survey Routes in South Dakota

Routes recording Great Egret in South Dakota.
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 →
Volga1220171989
Veblen520142001
Britton420232000
Turton320072007
Tripp219991999
Howard220051986
Long Lake220172004
White Lake120001988
Chamberlain120112011
Raymond120192005
Roswell120141989
Broadland120091999
Crow Creek120212009
Wilmot120102008
Lane 2120052005

Great Egret Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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