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

Ring-necked Duck Population Trend in California

All statesWaterfowl

Ring-necked Duck in California has surged: up 903% on the route-weighted index since 1993.

+903%Since 1993TrendPercent 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 →
13Routes 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 →
25YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Ring-necked 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 →

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 →

Ring-necked Duck has surged in California: up 903% on the route-weighted index since 1993.

Ring-necked Duck Population Forecast in California

If the recent trend holds, Ring-necked Duck in California is projected to fall about 54% by 2029 — from 0.35 in 2024 to a central estimate of 0.16 (95% range 0.03–0.30). A 5-year backtest shows a typical error of ±62.2%, with 60% of held-out values landing inside the 95% band.

-54%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 →
0.16Projected 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 →
0.03–0.3095% 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 →
±62.2%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, Ring-necked Duck in California is projected to fall about 54% by 2029 — from 0.35 in 2024 to a central estimate of 0.16 (95% range 0.03–0.30). A 5-year backtest shows a typical error of ±62.2%, with 60% of held-out values landing inside the 95% band.19762029
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 →
20250.150.010.29
20260.150.010.29
20270.160.020.30
20280.160.020.30
20290.160.030.30

Ring-necked Duck Survey Routes in California

Routes recording Ring-necked 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 →
Dorris2220171994
Likely1820242008
Clear Lk Res1520171995
Madeline1520242017
Crescent Cty519761976
Crowder Flat220072002
Nubieber220152015
Tehama119931981
Honey Lake120002000
Iron Gate120091998
Yreka119961996
Benton120232023
Hughson120052005

Ring-necked Duck Population Trend in Other States

alabamaalaskaarizonacoloradoidahoiowamainemichiganminnesotamontananebraskanevadanew-hampshirenew-yorknorth-dakotaohiooregonsouth-dakotautahvermontwashingtonwisconsinwyoming

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