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Species · Montana · BBS 2026 Release · 1966–2025

Gadwall Population Trend in Montana

All statesWaterfowl

Gadwall in Montana has held roughly steady: up 1% on the route-weighted index since 1972.

+1%Since 1972TrendPercent 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 →
70Routes 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 →
54YearsYears 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 MontanaNotable 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 Montana. See the full index history below.

Gadwall Population Forecast in Montana

If the recent trend holds, Gadwall in Montana is projected to rise about 41% by 2030 — from 0.98 in 2025 to a central estimate of 1.4 (95% range 0.00–3.2). A 5-year backtest shows a typical error of ±44.8%, with 100% of held-out values landing inside the 95% band.

+41%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 →
1.4Projected 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 →
0.00–3.295% 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 →
±44.8%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 Montana is projected to rise about 41% by 2030 — from 0.98 in 2025 to a central estimate of 1.4 (95% range 0.00–3.2). A 5-year backtest shows a typical error of ±44.8%, with 100% of held-out values landing inside the 95% band.19702030
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 →
20261.40.003.2
20271.40.003.2
20281.40.003.2
20291.40.003.2
20301.40.003.2

Gadwall Survey Routes in Montana

Routes recording Gadwall in Montana.
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 →
Sunburst1220071970
Virgelle820251979
Brandenberg820072007
Two Dot720251987
Ingomar720251978
Winnett720252018
Chinook620252015
Sun River620232017
Great Falls520231972
Locate520221982
Red Rock520221973
Saco520252015
Westby520252015
Dinosaurs H.M.520252018
Coleman Coulee520242017
Wheat Basin520252018
Beaverhead420231974
Gildford420242015
Ester Lake420252015
Glentana420252015
Cleveland320141988
Oswego320231978
Leroy320181980
Roy320251988
Webster320251978

Gadwall Population Trend in Other States

alaskaarizonacaliforniacoloradodelawareidahoillinoisindianaiowakansasmassachusettsmichiganminnesotamissourinebraskanevadanew-jerseynew-mexiconew-yorknorth-dakotaoklahomaoregonpennsylvaniarhode-islandsouth-dakotatexasutahvermontwashingtonwisconsinwyoming

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