BirdAnalyst
Species · North Dakota · BBS 2026 Release · 1966–2025

American Bittern Population Trend in North Dakota

All statesWetland birds

American Bittern in North Dakota has risen sharply: up 53% on the route-weighted index since 1969.

+53%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 →
45Routes 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 American Bittern 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 →

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

American Bittern has risen sharply in North Dakota: up 53% on the route-weighted index since 1969.

American Bittern Population Forecast in North Dakota

If the recent trend holds, American Bittern in North Dakota is projected to rise about 23% by 2030 — from 1.7 in 2025 to a central estimate of 2.1 (95% range 0.84–3.3). A 5-year backtest shows a typical error of ±51.2%, with 80% of held-out values landing inside the 95% band.

+23%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 →
2.1Projected 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 →
0.84–3.395% 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 →
±51.2%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, American Bittern in North Dakota is projected to rise about 23% by 2030 — from 1.7 in 2025 to a central estimate of 2.1 (95% range 0.84–3.3). A 5-year backtest shows a typical error of ±51.2%, with 80% of held-out values landing inside the 95% band.19672030
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 →
20262.00.773.3
20272.00.793.3
20282.10.813.3
20292.10.823.3
20302.10.843.3

American Bittern Survey Routes in North Dakota

Routes recording American Bittern 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 →
Cooperstown1020251969
Danzig 21020252019
Montpelier820251996
Buchanan720251967
Horsehead Lk420251980
Lakota420091974
Lakota 2420242010
Forman320241968
Denbigh320221969
Bowman320231967
Braddock320231988
Edgeley220251987
Wimbledon220251989
Bowesmont220111969
Webster220221992
Niles220251992
Regan220231970
Carpio220231970
Loraine220191994
Stanley220181972
Lark219821969
Gorham220071975
Powers Lake220231980
Walcott120141974
Sydney119811968

American Bittern Population Trend in Other States

alaskacaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaslouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorkohiooklahomaoregonpennsylvaniasouth-carolinasouth-dakotatexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.