BirdAnalyst
Species · BCR 15 · BBS 2025 Release · 1966–2024

Wood Duck In Sierra Nevada

All regionsSierra NevadaWaterfowl

Wood Duck in Sierra Nevada has fallen sharply: down 74% on the route-weighted index since 1985.

-74%Since 1985TrendPercent 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 →
6Routes 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 →
23YearsYears 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 declinecomputed 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 →

Wood Duck has fallen sharply in Sierra Nevada: down 74% on the route-weighted index since 1985.

Wood Duck In Sierra Nevada Population Forecast

If the recent trend holds, Wood Duck in Sierra Nevada is projected to rise about 125% by 2024 — from 0.08 in 2019 to a central estimate of 0.18 (95% range 0.00–0.46). A 5-year backtest shows a typical error of ±269.4%, with 100% of held-out values landing inside the 95% band.

+125%Change by 2024TrendPercent 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 →
0.18Projected 2024 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.4695% 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 →
±269.4%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 Sierra Nevada is projected to rise about 125% by 2024 — from 0.08 in 2019 to a central estimate of 0.18 (95% range 0.00–0.46). A 5-year backtest shows a typical error of ±269.4%, with 100% of held-out values landing inside the 95% band.19772024
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 →
20200.180.000.47
20210.180.000.47
20220.180.000.47
20230.180.000.46
20240.180.000.46

Routes In Sierra Nevada

Routes recording Wood Duck in Sierra Nevada.
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 →
Bass LakeCALIFORNIA51977
GeneseeCALIFORNIA32015
PaxtonCALIFORNIA22019
Tuolumne GroveCALIFORNIA12016
Higgins CornCALIFORNIA12013
Hat CreekCALIFORNIA11997

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