BirdAnalyst
Species · Nebraska · BBS 2026 Release · 1966–2025

Gadwall Population Trend in Nebraska

All statesWaterfowl

Gadwall in Nebraska has declined: down 50% on the route-weighted index since 1969.

-50%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 →
15Routes 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 →
48YearsYears 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 NebraskaNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Gadwall in Nebraska. See the full index history below.

Gadwall Population Forecast in Nebraska

If the recent trend holds, Gadwall in Nebraska is projected to rise about 116% by 2030 — from 0.07 in 2025 to a central estimate of 0.14 (95% range 0.00–0.47). A 5-year backtest shows a typical error of ±240.2%, with 100% of held-out values landing inside the 95% band.

+116%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 →
0.14Projected 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 →
0.00–0.4795% 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 →
±240.2%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, Gadwall in Nebraska is projected to rise about 116% by 2030 — from 0.07 in 2025 to a central estimate of 0.14 (95% range 0.00–0.47). A 5-year backtest shows a typical error of ±240.2%, 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 →
20260.150.000.47
20270.150.000.47
20280.150.000.47
20290.150.000.47
20300.140.000.47

Gadwall Survey Routes in Nebraska

Routes recording Gadwall in Nebraska.
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 →
Piester Lake620161967
Arthur420242022
Kennedy420241995
Swan Lake320211983
Agate 2220092009
Oglala Nat. Grass.220151999
Ringgold220052003
Crescent Lk220251980
Murray Lake220101997
Pine Ridge220002000
Nenzel220212021
Wheeler Co220251982
Table120172007
Gordon120131976
Brownlee120181992

Gadwall Population Trend in Other States

alaskaarizonacaliforniacoloradodelawareidahoillinoisindianaiowakansasmassachusettsmichiganminnesotamissourimontananevadanew-jerseynew-mexiconew-yorknorth-dakotaoklahomaoregonpennsylvaniarhode-islandsouth-dakotatexasutahvermontwashingtonwisconsinwyoming

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