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

Green-winged Teal Population Trend in North Dakota

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Green-winged Teal in North Dakota has surged: up 160% on the route-weighted index since 1969.

+160%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 →
44Routes 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 Green-winged Teal 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 →

Green-winged Teal has surged in North Dakota: up 160% on the route-weighted index since 1969.

Green-winged Teal Population Forecast in North Dakota

If the recent trend holds, Green-winged Teal in North Dakota is projected to fall about 35% by 2029 — from 1.7 in 2024 to a central estimate of 1.1 (95% range 0.28–1.9). A 5-year backtest shows a typical error of ±30.5%, with 100% of held-out values landing inside the 95% band.

-35%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 →
1.1Projected 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 →
0.28–1.995% 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 →
±30.5%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, Green-winged Teal in North Dakota is projected to fall about 35% by 2029 — from 1.7 in 2024 to a central estimate of 1.1 (95% range 0.28–1.9). A 5-year backtest shows a typical error of ±30.5%, 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 →
20251.10.231.9
20261.10.241.9
20271.10.261.9
20281.10.271.9
20291.10.281.9

Green-winged Teal Survey Routes in North Dakota

Routes recording Green-winged Teal 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 2820242019
Forman720231969
Buchanan620241967
Wild Rose620241982
Gorham519821982
Lakota 2520242010
Walcott420142014
Lakota420091968
Ft Yates419721972
Sydney319801979
Webster320241992
Niles320241992
Regan320191982
Denbigh320151982
Douglas Crk320231982
Edgeley220241980
Kempton219971967
Wimbledon220241996
Horsehead Lk220241980
Bowesmont220141970
Nash220131999
Rolla220241969
Bowman220241970
Bentley220132001
Powers Lake220221980

Green-winged Teal Population Trend in Other States

alaskaarizonacaliforniacoloradoidahoillinoisindianaiowakansasmainemichiganminnesotamissourimontananebraskanevadanew-hampshirenew-mexiconew-yorkoklahomaoregonpennsylvaniasouth-dakotatexasutahvermontwashingtonwisconsinwyoming

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