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Species · Wisconsin · BBS 2025 Release · 1966–2024

Black-crowned Night Heron Population Trend in Wisconsin

All statesWetland birds

Black-crowned Night Heron in Wisconsin has edged down: down 21% on the route-weighted index since 1968.

-21%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 →
24Routes 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 →
42YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Black-crowned Night 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 Black-crowned Night Heron in Wisconsin. See the full index history below.

Black-crowned Night Heron Population Forecast in Wisconsin

If the recent trend holds, Black-crowned Night Heron in Wisconsin is projected to stay roughly flat through 2029, near 0.03 (95% range 0.00–0.14). A 5-year backtest shows a typical error of ±183.7%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.03Projected 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 →
0.00–0.1495% 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 →
±183.7%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, Black-crowned Night Heron in Wisconsin is projected to stay roughly flat through 2029, near 0.03 (95% range 0.00–0.14). A 5-year backtest shows a typical error of ±183.7%, 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 →
20250.030.000.14
20260.030.000.14
20270.030.000.14
20280.030.000.14
20290.030.000.14

Black-crowned Night Heron Survey Routes in Wisconsin

Routes recording Black-crowned Night 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 →
Brownsville519901976
Omro 2420092003
Princeton419931993
Pt Washingtn420151998
Dresser319781978
Manitowoc320242024
Rolling Pr320131979
Casco219941991
Fall River219691969
Hudson119951977
Weyerhauser120222022
Phillips120002000
Hollister119811981
Esdaile119871987
Unity120172017
Saxeville119811981
Manawa120001984
Omro120001967
Pardeeville120181986
Beaver Dam119861968
Eden119671967
Kiel120112000
Wiota119891989
Hebron119921966

Black-crowned Night Heron Population Trend in Other States

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

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