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

Gadwall Population Trend in Nevada

All statesWaterfowl

Gadwall in Nevada has risen sharply: up 74% on the route-weighted index since 1971.

+74%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 →
23Routes 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 →
43YearsYears 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 NevadaNotable 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 risen sharply in Nevada: up 74% on the route-weighted index since 1971.

Gadwall Population Forecast in Nevada

If the recent trend holds, Gadwall in Nevada is projected to rise about 149% by 2029 — from 0.50 in 2024 to a central estimate of 1.2 (95% range 0.00–2.7). A 5-year backtest shows a typical error of ±579.5%, with 60% of held-out values landing inside the 95% band.

+149%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 →
1.2Projected 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 →
0.00–2.795% 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 →
±579.5%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, Gadwall in Nevada is projected to rise about 149% by 2029 — from 0.50 in 2024 to a central estimate of 1.2 (95% range 0.00–2.7). A 5-year backtest shows a typical error of ±579.5%, with 60% of held-out values landing inside the 95% band.19682029
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 →
20251.20.002.7
20261.20.002.7
20271.20.002.7
20281.20.002.7
20291.20.002.7

Gadwall Survey Routes in Nevada

Routes recording Gadwall in Nevada.
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 →
Ruby Valley2020001997
Virgin Creek920181995
Majors Place819991968
Cortez420241968
Toiyabe Nf420102010
Nixon420092009
Bald Mtn.420241992
Chimney Res.420242023
Dobbin Creek320161972
Fallon320221993
Dinner Sta219711971
Ranchogrande219951995
Eureka220001990
Ruby Valley 2220212004
Hiko220011970
Gardnerville 2220242024
Midas120191996
Sand Pass120122010
Sheldon Nwr120092001
Austin120172017
Ash Meadows120192010
Illipah120182013
Gardnerville120051996

Gadwall Population Trend in Other States

alaskaarizonacaliforniacoloradodelawareidahoillinoisiowakansasmassachusettsmichiganminnesotamissourimontananebraskanew-jerseynew-mexiconew-yorknorth-dakotaoklahomaoregonpennsylvaniarhode-islandsouth-dakotatexasutahvermontwashingtonwisconsinwyoming

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