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

Great Egret Population Trend in Illinois

All statesWetland birds

Great Egret in Illinois has increased: up 33% on the route-weighted index since 1968.

+33%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 →
48YearsYears 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 →

No notable trend signals for Great Egret in Illinois. See the full index history below.

Great Egret Population Forecast in Illinois

If the recent trend holds, Great Egret in Illinois is projected to rise about 15% by 2029 — from 0.60 in 2024 to a central estimate of 0.69 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±232.1%, with 100% of held-out values landing inside the 95% band.

+15%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 →
0.69Projected 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 →
0.00–1.595% 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 →
±232.1%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, Great Egret in Illinois is projected to rise about 15% by 2029 — from 0.60 in 2024 to a central estimate of 0.69 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±232.1%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20250.660.001.5
20260.670.001.5
20270.670.001.5
20280.680.001.5
20290.690.001.5

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
Chandlervill1219741973
Royalton920232015
Mt Vernon820061997
Lake Summerset720082004
Mascoutah Lk520231995
Yorkville420182001
Belknap420242000
Eldred420042004
Geneseo320141989
Pawnee320002000
Beaverdam Lk320141992
Seneca320131993
Duncan Mills320022002
Barrington220121987
Wayne220241978
Sherburnvill220142014
Mackinaw220021968
Bluff Spgs219981996
Columbia220241987
Guilford120171998
Mill Creek120182018
Payson120212021

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 2026-05-22.