BirdAnalyst
Species · North Dakota · BBS 2025 Release · 1966–2024

Black-crowned Night Heron Population Trend in North Dakota

All statesWetland birds

Black-crowned Night Heron in North Dakota has edged up: up 11% on the route-weighted index since 1969.

+11%Since 1969TrendPercent 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 →
30Routes 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 →
56YearsYears 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 North DakotaNotable 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 North Dakota. See the full index history below.

Black-crowned Night Heron Population Forecast in North Dakota

If the recent trend holds, Black-crowned Night Heron in North Dakota is projected to rise about 20% by 2029 — from 0.78 in 2024 to a central estimate of 0.94 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±91.9%, with 100% of held-out values landing inside the 95% band.

+20%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 →
0.94Projected 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 →
0.00–2.195% 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 →
±91.9%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 North Dakota is projected to rise about 20% by 2029 — from 0.78 in 2024 to a central estimate of 0.94 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±91.9%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.910.002.1
20260.920.002.1
20270.920.002.1
20280.930.002.1
20290.940.002.1

Black-crowned Night Heron Survey Routes in North Dakota

Routes recording Black-crowned Night Heron in North Dakota.
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 →
Braddock1720191988
Forman1120151968
Buchanan820241967
Lake George620211970
Danzig520131988
Lakota420091968
Sheyenne Lk320221980
Emerado219761974
Horsehead Lk220241980
Rolla220172017
Niles220241994
Denbigh220171976
Wild Rose220241982
Montpelier220242000
Danzig 2220222021
Lakota 2220242010
Edgeley120192009
Kempton120022002
Cooperstown120241970
Wimbledon120241997
Webster120161995
Regan120131975
Ft Yates119891989
Dunn Center119821982
Carpio120131978

Black-crowned Night Heron Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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