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

Green Heron Population Trend in Wisconsin

All statesWetland birds

Green Heron in Wisconsin has increased: up 29% on the route-weighted index since 1968.

+29%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 →
59YearsYears 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 2030, near 0.45 (95% range 0.02–0.87). A 5-year backtest shows a typical error of ±14.1%, with 100% of held-out values landing inside the 95% band.

-2%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 →
0.45Projected 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 →
0.02–0.8795% 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 →
±14.1%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, Green Heron in Wisconsin is projected to stay roughly flat through 2030, near 0.45 (95% range 0.02–0.87). A 5-year backtest shows a typical error of ±14.1%, 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 →
20260.470.040.89
20270.460.040.89
20280.460.030.88
20290.450.030.87
20300.450.020.87

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 →
Fall River420251970
Kiel420221999
Raymond320251970
Loraine220131967
Weyerhauser220251966
Exeland220231970
Holway219871972
Phillips220221977
Rib Lake220251969
Popple River219741974
Crandon220091969
Unity220241968
Stratford220251980
Wis Rapids220221969
Elderon220241967
Omro220001967
Manitowoc220241966
Kendall220231967
Pardeeville220251971
Brownsville220181975
Pt Washingtn220241969
Hazel Green220221966
Wiota220251975
Mount Horeb219881967
Colby220181999

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 2026-08-14.