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

Green Heron Population Trend in Wisconsin

All statesWetland birds

Green Heron in Wisconsin has edged up: up 18% on the route-weighted index since 1968.

+18%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 →
92Routes 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 Green 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 Green Heron in Wisconsin. See the full index history below.

Green Heron Population Forecast in Wisconsin

If the recent trend holds, Green Heron in Wisconsin is projected to stay roughly flat through 2029, near 0.45 (95% range 0.02–0.88). A 5-year backtest shows a typical error of ±49.6%, with 100% of held-out values landing inside the 95% band.

+4%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 →
0.45Projected 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 →
0.02–0.8895% 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 →
±49.6%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, Green Heron in Wisconsin is projected to stay roughly flat through 2029, near 0.45 (95% range 0.02–0.88). A 5-year backtest shows a typical error of ±49.6%, 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 →
20250.470.040.90
20260.470.040.89
20270.460.030.89
20280.450.030.88
20290.450.020.88

Green Heron Survey Routes in Wisconsin

Routes recording Green 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 →
Kiel420221999
Weyerhauser320241966
Rib Lake320231969
Trempealeau320161970
Pardeeville320241971
Fall River320241970
Gresham320242002
Dresser220211968
Loraine220131967
Exeland220231970
Gilman220221966
Holway219871972
Phillips220221977
Popple River219741974
Crandon220091969
Unity220241968
Stratford220231980
Wis Rapids220221969
Elderon220241967
Omro220001967
Manitowoc220241966
Casco220231970
Kendall220231967
Brownsville220181975
Pt Washingtn220241969

Green Heron Population Trend in Other States

alabamaarizonaarkansascaliforniaconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawashingtonwest-virginia

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