BirdAnalyst
Species · Oregon · BBS 2025 Release · 1966–2024

Gadwall Population Trend in Oregon

All statesWaterfowl

Gadwall in Oregon has surged: up 473% on the route-weighted index since 1971.

+473%Since 1971TrendPercent 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 →
37Routes 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 →
55YearsYears 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 OregonNotable 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 Oregon: up 473% on the route-weighted index since 1971.

Gadwall Population Forecast in Oregon

If the recent trend holds, Gadwall in Oregon is projected to rise about 92% by 2029 — from 1.2 in 2024 to a central estimate of 2.3 (95% range 0.00–7.2). A 5-year backtest shows a typical error of ±291.2%, with 100% of held-out values landing inside the 95% band.

+92%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 →
2.3Projected 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 →
0.00–7.295% 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 →
±291.2%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 Oregon is projected to rise about 92% by 2029 — from 1.2 in 2024 to a central estimate of 2.3 (95% range 0.00–7.2). A 5-year backtest shows a typical error of ±291.2%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20252.20.007.1
20262.20.007.1
20272.30.007.2
20282.30.007.2
20292.30.007.2

Gadwall Survey Routes in Oregon

Routes recording Gadwall in Oregon.
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 →
Warner Vally4820241993
Fish Lake2520241972
Modoc Point 21220242024
Merrill920221994
Malheur Nwr819961986
Catlow Rim720241993
Bly619951992
Flook Lake620241995
Lapham Res.519941994
Princeton519851972
Zumwalt420001998
Nicolai Mtn.420172002
Bly 2420242007
Blizzard Gap420231984
Trout Creek320171996
Bridgeport320121995
Chinchalo320241993
Three Forks220242004
Blitzen 2220242024
Scappoose220082008
Fandango Can219981998
Modoc Point220181969
Blitzen219831983
Willow Spg219711969
Adair220212004

Gadwall Population Trend in Other States

alaskaarizonacaliforniacoloradodelawareidahoillinoisiowakansasmassachusettsmichiganminnesotamissourimontananebraskanevadanew-jerseynew-mexiconew-yorknorth-dakotaoklahomapennsylvaniarhode-islandsouth-dakotatexasutahvermontwashingtonwisconsinwyoming

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