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

American Bittern Population Trend in North Dakota

All statesWetland birds

American Bittern in North Dakota has surged: up 104% on the route-weighted index since 1969.

+104%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 →
57YearsYears 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 surged in North Dakota: up 104% 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 fall about 18% by 2029 — from 2.6 in 2024 to a central estimate of 2.1 (95% range 0.84–3.4). A 5-year backtest shows a typical error of ±50.9%, with 80% of held-out values landing inside the 95% band.

-18%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 →
2.1Projected 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 →
0.84–3.495% 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 →
±50.9%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, American Bittern in North Dakota is projected to fall about 18% by 2029 — from 2.6 in 2024 to a central estimate of 2.1 (95% range 0.84–3.4). A 5-year backtest shows a typical error of ±50.9%, with 80% 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 →
20252.00.783.3
20262.10.793.3
20272.10.813.3
20282.10.833.4
20292.10.843.4

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 →
Danzig 21620242019
Cooperstown1120241969
Sheyenne Lk1020241980
Horsehead Lk920241980
Buchanan820241967
Lakota420091974
Lakota 2420242010
Forman320241968
Denbigh320221969
Bowman320231967
Edgeley220241987
Bowesmont220111969
Webster220221992
Niles220231992
Regan220221970
Carpio220231970
Loraine220191994
Stanley220181972
Lark219821969
Gorham220071975
Powers Lake220231980
Braddock220221988
Walcott120141974
Sydney119811968
Lake George120211967

American Bittern Population Trend in Other States

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

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