BirdAnalyst
Species · Illinois · BBS 2026 Release · 1966–2025

Great Egret Population Trend in Illinois

All statesWetland birds

Great Egret in Illinois has surged: up 100% on the route-weighted index since 1968.

+100%Since 1968TrendPercent 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 →
49Routes 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 →
49YearsYears 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 IllinoisNotable 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 Illinois: up 100% on the route-weighted index since 1968.

Great Egret Population Forecast in Illinois

If the recent trend holds, Great Egret in Illinois is projected to stay roughly flat through 2030, near 0.70 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±100.3%, with 100% of held-out values landing inside the 95% band.

+1%Change by 2030TrendPercent 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 →
0.70Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–1.595% 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 →
±100.3%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 Illinois is projected to stay roughly flat through 2030, near 0.70 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±100.3%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20260.670.001.5
20270.680.001.5
20280.690.001.5
20290.690.001.5
20300.700.001.5

Great Egret Survey Routes in Illinois

Routes recording Great Egret in Illinois.
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 →
Gulfport12720131983
Belleview3620241966
Shannon1419931993
Jamestown1320251991
Chandlervill1219741973
Pulaski1220251974
Mt Vernon820061997
Karnak820252002
Wayne720251978
Lake Summerset720082004
Mascoutah Lk520231995
Darmstadt520252013
Yorkville420182001
Royalton420252015
Eldred420042004
Geneseo320141989
Pawnee320002000
Beaverdam Lk320141992
Seneca320131993
Duncan Mills320022002
Barrington220121987
Sherburnvill220142014
Mackinaw220021968
Bluff Spgs219981996
Columbia220241987

Great Egret Population Trend in Other States

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

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.