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

Great Blue Heron Population Trend in Wisconsin

All statesWetland birds

Great Blue Heron in Wisconsin has edged down: down 10% on the route-weighted index since 1968.

-10%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 →
97Routes 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 →
58YearsYears 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 Blue Heron Trends in WisconsinNotable 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 Blue Heron in Wisconsin. See the full index history below.

Great Blue Heron Population Forecast in Wisconsin

If the recent trend holds, Great Blue Heron in Wisconsin is projected to rise about 22% by 2029 — from 0.90 in 2024 to a central estimate of 1.1 (95% range 0.00–2.3). A 5-year backtest shows a typical error of ±101.8%, with 100% of held-out values landing inside the 95% band.

+22%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 →
1.1Projected 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 →
0.00–2.395% 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 →
±101.8%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 Blue Heron in Wisconsin is projected to rise about 22% by 2029 — from 0.90 in 2024 to a central estimate of 1.1 (95% range 0.00–2.3). A 5-year backtest shows a typical error of ±101.8%, 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 →
20251.10.002.3
20261.10.002.3
20271.10.002.3
20281.10.002.3
20291.10.002.3

Great Blue Heron Survey Routes in Wisconsin

Routes recording Great Blue Heron in Wisconsin.
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 →
Hatfield2119981970
Hudson1020241967
Omro720011966
Pt Washingtn620241969
Omro 2620242002
Montreal420121974
Raymond420241967
Verona420241991
Stratford320241966
Elderon320241966
Fall River320231972
Paris320241967
River Falls320181999
Prairie Du Chien320241998
Land O Lakes220161967
Dresser220231966
Loraine220211966
Couderay220191974
Gilman220191971
Irma220241968
Popple River219941970
Washington I220241968
Mather220131966
Wis Rapids220171966
Manawa220221967

Great Blue Heron Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawyoming

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