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

Ruddy Duck Population Trend in California

All statesWaterfowl

Ruddy Duck in California has increased: up 42% on the route-weighted index since 1972.

+42%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 →
50Routes 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 Ruddy 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 Ruddy Duck in California. See the full index history below.

Ruddy Duck Population Forecast in California

If the recent trend holds, Ruddy Duck in California is projected to rise about 16% by 2029 — from 0.44 in 2024 to a central estimate of 0.51 (95% range 0.00–1.8). A 5-year backtest shows a typical error of ±154.7%, with 100% of held-out values landing inside the 95% band.

+16%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 →
0.51Projected 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 →
0.00–1.895% 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 →
±154.7%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, Ruddy Duck in California is projected to rise about 16% by 2029 — from 0.44 in 2024 to a central estimate of 0.51 (95% range 0.00–1.8). A 5-year backtest shows a typical error of ±154.7%, with 100% of held-out values landing inside the 95% band.19702029
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 →
20250.550.001.8
20260.540.001.8
20270.530.001.8
20280.520.001.8
20290.510.001.8

Ruddy Duck Survey Routes in California

Routes recording Ruddy 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 →
Niland6520211973
Likely1520241990
Mark West1519781978
Dorris1420191972
Benton1020241974
Adelaida1020151988
Collegeville919871987
Anza719751973
Jofegan 2620242024
Haiwee Res619921992
Lockwood620231981
Buena Vista620192019
Madeline520242016
Foster Park519751975
Ora Loma519951973
S Catalina519981993
Iron Gate420081989
Jacumba419951995
Carrizo Pln419781978
Macdoel419951974
Big Bear419861972
Ingalls419941989
Cp. Pendleton419911970
Clear Lk Res319991981
Cedarville320172003

Ruddy Duck Population Trend in Other States

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