BirdAnalyst
Species · BCR 32 · BBS 2025 Release · 1966–2024

Ruddy Duck In Coastal California

All regionsCoastal CaliforniaWaterfowl

Ruddy Duck in Coastal California has declined: down 44% on the route-weighted index since 1973.

-44%Since 1973TrendPercent 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 →
31Routes 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 →
51YearsYears 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 →

No notable trend signals for Ruddy Duck in Coastal California. See the full index history below.

Ruddy Duck In Coastal California Population Forecast

If the recent trend holds, Ruddy Duck in Coastal California is projected to fall about 51% by 2029 — from 0.23 in 2024 to a central estimate of 0.12 (95% range 0.00–0.40). A 5-year backtest shows a typical error of ±117.5%, with 100% of held-out values landing inside the 95% band.

-51%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 →
0.12Projected 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 →
0.00–0.4095% 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 →
±117.5%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, Ruddy Duck in Coastal California is projected to fall about 51% by 2029 — from 0.23 in 2024 to a central estimate of 0.12 (95% range 0.00–0.40). A 5-year backtest shows a typical error of ±117.5%, 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 →
20250.120.000.41
20260.120.000.41
20270.120.000.41
20280.120.000.41
20290.120.000.40

Routes In Coastal California

Routes recording Ruddy Duck in Coastal 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 →
Mark WestCALIFORNIA151978
AdelaidaCALIFORNIA102015
CollegevilleCALIFORNIA91987
AnzaCALIFORNIA71975
LockwoodCALIFORNIA62023
Buena VistaCALIFORNIA62019
Jofegan 2CALIFORNIA62024
Foster ParkCALIFORNIA51975
S CatalinaCALIFORNIA51998
Ora LomaCALIFORNIA51995
Big BearCALIFORNIA41986
Cp. PendletonCALIFORNIA41991
JacumbaCALIFORNIA41995
Carrizo PlnCALIFORNIA41978
PescaderoCALIFORNIA32024
Tres PinosCALIFORNIA22000
OilfieldsCALIFORNIA21976
HollisterCALIFORNIA21993
CoalingaCALIFORNIA21999
Elizabeth LkCALIFORNIA21985
CordovaCALIFORNIA21981
WestleyCALIFORNIA21993
TehamaCALIFORNIA21997
PolomaCALIFORNIA22024
HughsonCALIFORNIA12023

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