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

Clark's Grebe In Coastal California

All regionsCoastal CaliforniaWetland birds

Clark's Grebe in Coastal California has surged: up 107% on the route-weighted index since 1988.

+107%Since 1988TrendPercent 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 RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
37YearsYears 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 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 →

Clark's Grebe has surged in Coastal California: up 107% on the route-weighted index since 1988.

Clark's Grebe In Coastal California Population Forecast

If the recent trend holds, Clark's Grebe in Coastal California is projected to stay roughly flat through 2029, near 0.22 (95% range 0.02–0.42). A 5-year backtest shows a typical error of ±89.8%, with 80% of held-out values landing inside the 95% band.

+3%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 →
0.22Projected 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 →
0.02–0.4295% 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 →
±89.8%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, Clark's Grebe in Coastal California is projected to stay roughly flat through 2029, near 0.22 (95% range 0.02–0.42). A 5-year backtest shows a typical error of ±89.8%, with 80% of held-out values landing inside the 95% band.19862029
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 →
20250.200.010.40
20260.210.010.41
20270.210.010.41
20280.210.020.41
20290.220.020.42

Routes In Coastal California

Routes recording Clark's Grebe 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 →
Buena VistaCALIFORNIA62019
Lake BerryessaCALIFORNIA42024
CoyoteCALIFORNIA42024
San YsidroCALIFORNIA31991
HughsonCALIFORNIA22024
MoragaCALIFORNIA22010
Bartlett SpsCALIFORNIA22015
Foster ParkCALIFORNIA11993
HollisterCALIFORNIA12001
FolsomCALIFORNIA11987
CopperopolisCALIFORNIA12021
Ora LomaCALIFORNIA12023
Staten Is.CALIFORNIA12010

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