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

Pied-billed Grebe In Coastal California

All regionsCoastal CaliforniaWetland birds

Pied-billed Grebe in Coastal California has edged down: down 14% on the route-weighted index since 1971.

-14%Since 1971TrendPercent 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 →
57Routes 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 →
54YearsYears 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 →

No notable trend signals for Pied-billed Grebe in Coastal California. See the full index history below.

Pied-billed Grebe In Coastal California Population Forecast

If the recent trend holds, Pied-billed Grebe in Coastal California is projected to fall about 29% by 2029 — from 0.36 in 2024 to a central estimate of 0.26 (95% range 0.00–0.57). A 5-year backtest shows a typical error of ±155.1%, with 100% of held-out values landing inside the 95% band.

-29%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 →
0.26Projected 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 →
0.00–0.5795% 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 →
±155.1%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, Pied-billed Grebe in Coastal California is projected to fall about 29% by 2029 — from 0.36 in 2024 to a central estimate of 0.26 (95% range 0.00–0.57). A 5-year backtest shows a typical error of ±155.1%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20250.260.000.57
20260.260.000.57
20270.260.000.57
20280.260.000.57
20290.260.000.57

Routes In Coastal California

Routes recording Pied-billed 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 →
Point ReyesCALIFORNIA102010
Staten Is.CALIFORNIA62024
JacumbaCALIFORNIA51995
JacksonCALIFORNIA51986
PenningtonCALIFORNIA32015
Harbor LakeCALIFORNIA31990
El ToroCALIFORNIA31980
VentucopaCALIFORNIA31997
CoyoteCALIFORNIA32024
Red BluffCALIFORNIA22011
ColmaCALIFORNIA21971
HughsonCALIFORNIA22024
Yokohl ValCALIFORNIA21993
CoalingaCALIFORNIA22001
Big BearCALIFORNIA21986
AuburnCALIFORNIA21980
OnoCALIFORNIA22009
Mesa GrandeCALIFORNIA21986
AdelaidaCALIFORNIA22015
Carrizo PlnCALIFORNIA21978
GlennCALIFORNIA22015
WestleyCALIFORNIA22006
OrovilleCALIFORNIA22010
OnealsCALIFORNIA22024
AthloneCALIFORNIA21989

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