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Species · California · BBS 2025 Release · 1966–2024

Eared Grebe Population Trend in California

All statesWetland birds

Eared Grebe in California has surged: up 83% on the route-weighted index since 1973.

+83%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 →
24Routes 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 →
52YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Eared Grebe 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 →

Eared Grebe has surged in California: up 83% on the route-weighted index since 1973.

Eared Grebe Population Forecast in California

If the recent trend holds, Eared Grebe in California is projected to rise about 203% by 2029 — from 1.3 in 2024 to a central estimate of 4.0 (95% range 0.00–10). A 5-year backtest shows a typical error of ±2327.6%, with 100% of held-out values landing inside the 95% band.

+203%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 →
4.0Projected 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 →
0.00–1095% 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 →
±2327.6%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, Eared Grebe in California is projected to rise about 203% by 2029 — from 1.3 in 2024 to a central estimate of 4.0 (95% range 0.00–10). A 5-year backtest shows a typical error of ±2327.6%, with 100% of held-out values landing inside the 95% band.19712029
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 →
20253.90.0010
20263.90.0010
20274.00.0010
20284.00.0010
20294.00.0010

Eared Grebe Survey Routes in California

Routes recording Eared Grebe 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 →
Benton12320241976
Big Bear6319861971
Dorris5020191972
Haiwee Res1620041997
Clear Lk Res1119991975
Cedarville619741974
Copperopolis620171991
Elizabeth Lk520161980
Madeline420222011
Orange Cove419801980
Kelso Valley219801980
Nubieber219851985
Likely220152015
Crowley Lake219821982
Ingalls219901976
Niland220031977
Eagle Lake120141973
Hullville119841984
Crowder Flat120132013
Sattley119931993
Foster Park119711971
Palo Verde120032003
Hat Creek120002000
Lakeshore119921992

Eared Grebe Population Trend in Other States

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