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

Wood Duck Population Trend in California

All statesWaterfowl

Wood Duck in California has edged up: up 24% on the route-weighted index since 1971.

+24%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 →
65Routes 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 Wood Duck Trends in CaliforniaNotable 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 Wood Duck in California. See the full index history below.

Wood Duck Population Forecast in California

If the recent trend holds, Wood Duck in California is projected to rise about 339% by 2029 — from 0.10 in 2024 to a central estimate of 0.43 (95% range 0.07–0.78). A 5-year backtest shows a typical error of ±835.2%, with 0% of held-out values landing inside the 95% band.

+339%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 →
0.43Projected 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 →
0.07–0.7895% 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 →
±835.2%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, Wood Duck in California is projected to rise about 339% by 2029 — from 0.10 in 2024 to a central estimate of 0.43 (95% range 0.07–0.78). A 5-year backtest shows a typical error of ±835.2%, with 0% 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 →
20250.410.050.76
20260.410.060.77
20270.420.060.77
20280.420.070.78
20290.430.070.78

Wood Duck Survey Routes in California

Routes recording Wood Duck in California.
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 →
Lockwood1020051974
Honeydew820122012
Orange Cove720091980
Iron Gate620191988
Nubieber520181993
Bass Lake519771977
Gold Hill520241979
Fall River Mills520072007
Yreka520111985
Pennington420091985
Adelaida420231990
Horse Creek320191970
Crowder Flat320072006
Dorris320171998
Mccloud319841984
Moraga320112011
Genesee320152007
Point Reyes320151998
Red Bluff220231970
Gazelle219911991
Redwood N.P.220091996
Glenn220181972
Hughson220241993
Hackamore220102007
Oroville220241978

Wood Duck Population Trend in Other States

alabamaarizonaarkansascoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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