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

Green-winged Teal Population Trend in California

All statesWaterfowl

Green-winged Teal in California has surged: up 235% on the route-weighted index since 1976.

+235%Since 1976TrendPercent 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 →
21Routes 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 →
40YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Green-winged Teal 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 →

Green-winged Teal has surged in California: up 235% on the route-weighted index since 1976.

Green-winged Teal Population Forecast in California

If the recent trend holds, Green-winged Teal in California is projected to fall about 37% by 2029 — from 0.07 in 2024 to a central estimate of 0.04 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±57.5%, with 60% of held-out values landing inside the 95% band.

-37%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 →
0.04Projected 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 →
0.00–0.0895% 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 →
±57.5%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, Green-winged Teal in California is projected to fall about 37% by 2029 — from 0.07 in 2024 to a central estimate of 0.04 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±57.5%, with 60% of held-out values landing inside the 95% band.19722029
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 →
20250.040.000.08
20260.040.000.08
20270.040.000.08
20280.040.000.08
20290.040.000.08

Green-winged Teal Survey Routes in California

Routes recording Green-winged Teal 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 →
Carrizo Pln1019781978
Chilcoot520242024
Last Chance520192011
Sattley419721972
Yreka320071986
Riovista219761976
Dorris220171974
Macdoel220112008
Clear Lk Res220041986
Ravendale220071996
Lake Hemet219811981
Crescent Cty119881988
Crowder Flat120032003
Likely120132011
Madeline120192012
Crowley Lake120132013
Honey Lake119991999
Cedarville120032003
Coyote119831983
Ingalls119771977
Benton120242015

Green-winged Teal Population Trend in Other States

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