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

Gadwall Population Trend in North Dakota

All statesWaterfowl

Gadwall in North Dakota has surged: up 223% on the route-weighted index since 1969.

+223%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 →
49Routes 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 Gadwall 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 →

Gadwall has surged in North Dakota: up 223% on the route-weighted index since 1969.

Gadwall Population Forecast in North Dakota

If the recent trend holds, Gadwall in North Dakota is projected to rise about 36% by 2030 — from 14 in 2025 to a central estimate of 20 (95% range 11–28). A 5-year backtest shows a typical error of ±20%, with 100% of held-out values landing inside the 95% band.

+36%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 →
20Projected 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 →
11–2895% 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 →
±20%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, Gadwall in North Dakota is projected to rise about 36% by 2030 — from 14 in 2025 to a central estimate of 20 (95% range 11–28). A 5-year backtest shows a typical error of ±20%, with 100% 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 →
2026191027
2027191027
2028191128
2029191128
2030201128

Gadwall Survey Routes in North Dakota

Routes recording Gadwall 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 →
Wild Rose11720251982
Edgeley3020251980
Horsehead Lk2620251980
Danzig 22520252019
Bowman2420251969
Carpio2320231969
Sheyenne Lk2220251980
Webster2120241989
Rolla2120241969
Buchanan1820251967
Lakota 21820252010
Forman1720251968
Danzig1720141982
Lakota1720091968
Sydney1619831967
Montpelier1320251995
Lake George1220231967
Regan1220251968
Wimbledon1120251989
Niles1120251989
Braddock1120231988
Cooperstown920251969
Denbigh720251970
Powers Lake720251980
Dickinson520251973

Gadwall Population Trend in Other States

alaskaarizonacaliforniacoloradodelawareidahoillinoisindianaiowakansasmassachusettsmichiganminnesotamissourimontananebraskanevadanew-jerseynew-mexiconew-yorkoklahomaoregonpennsylvaniarhode-islandsouth-dakotatexasutahvermontwashingtonwisconsinwyoming

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