BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

Gadwall In Great Basin

All regionsGreat BasinWaterfowl

Gadwall in Great Basin has surged: up 958% on the route-weighted index since 1970.

+958%Since 1970TrendPercent 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 →
117Routes In RegionSurvey 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 SignalsNotable 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 Great Basin: up 958% on the route-weighted index since 1970.

Gadwall In Great Basin Population Forecast

If the recent trend holds, Gadwall in Great Basin is projected to rise about 167% by 2029 — from 2.1 in 2024 to a central estimate of 5.5 (95% range 1.2–9.8). A 5-year backtest shows a typical error of ±327.6%, with 20% of held-out values landing inside the 95% band.

+167%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 →
5.5Projected 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 →
1.2–9.895% 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 →
±327.6%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 Great Basin is projected to rise about 167% by 2029 — from 2.1 in 2024 to a central estimate of 5.5 (95% range 1.2–9.8). A 5-year backtest shows a typical error of ±327.6%, with 20% 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 →
20255.30.959.6
20265.31.09.6
20275.41.19.7
20285.41.19.8
20295.51.29.8

Routes In Great Basin

Routes recording Gadwall in Great Basin.
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 →
DorrisCALIFORNIA2122019
LikelyCALIFORNIA732024
Warner VallyOREGON482024
Bear RiverUTAH412023
BentonCALIFORNIA382024
BrewsterWASHINGTON352018
Columbia NwrWASHINGTON342021
Fish LakeOREGON252024
MadelineCALIFORNIA222024
Ruby ValleyNEVADA202000
MacdoelCALIFORNIA142019
CedarvilleCALIFORNIA142019
Iron GateCALIFORNIA132019
OthelloWASHINGTON131991
Modoc Point 2OREGON122024
CallaoUTAH102024
Virgin CreekNEVADA92018
MerrillOREGON92022
Majors PlaceNEVADA81999
Malheur NwrOREGON81996
Catlow RimOREGON72024
Cedar HillIDAHO62024
BlyOREGON61995
Flook LakeOREGON62024
Crowley LakeCALIFORNIA52024

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