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

Double-crested Cormorant Population Trend in North Dakota

All statesWetland birds

Double-crested Cormorant in North Dakota has surged: up 686% on the route-weighted index since 1970.

+686%Since 1970TrendPercent 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 →
42Routes 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 Double-crested Cormorant 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 →

Double-crested Cormorant has surged in North Dakota: up 686% on the route-weighted index since 1970.

Double-crested Cormorant Population Forecast in North Dakota

If the recent trend holds, Double-crested Cormorant in North Dakota is projected to fall about 10% by 2029 — from 9.9 in 2024 to a central estimate of 8.9 (95% range 3.0–15). A 5-year backtest shows a typical error of ±113.9%, with 80% of held-out values landing inside the 95% band.

-10%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 →
8.9Projected 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 →
3.0–1595% 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 →
±113.9%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, Double-crested Cormorant in North Dakota is projected to fall about 10% by 2029 — from 9.9 in 2024 to a central estimate of 8.9 (95% range 3.0–15). A 5-year backtest shows a typical error of ±113.9%, 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 →
20258.32.414
20268.52.614
20278.62.715
20288.82.915
20298.93.015

Double-crested Cormorant Survey Routes in North Dakota

Routes recording Double-crested Cormorant 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 →
Horsehead Lk6320241982
Danzig4320141995
Stanley4320241970
Lakota 23020242010
Turtle Mtns2620241980
Webster2420241999
Sheyenne Lk2220241980
Danzig 22220242019
Abercrombie1320051982
Walcott920172017
Edgeley920232003
Wild Rose920241982
Montpelier920242000
Emerado820241980
Carpio620231974
Golva620192018
Braddock620221988
Cooperstown520221995
Buchanan520241967
Glen Ullin520001988
Lake George420191981
Loraine420191982
Douglas Crk420231986
Lakota320091979
Regan320221974

Double-crested Cormorant Population Trend in Other States

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

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