BirdAnalyst
Species · BCR 32 · BBS 2026 Release · 1966–2025

American Coot In Coastal California

All regionsCoastal CaliforniaWetland birds

American Coot in Coastal California has fallen sharply: down 58% on the route-weighted index since 1970.

-58%Since 1970TrendPercent 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 →
78Routes 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 →
57YearsYears 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 →

American Coot has fallen sharply in Coastal California: down 58% on the route-weighted index since 1970.

American Coot In Coastal California Population Forecast

If the recent trend holds, American Coot in Coastal California is projected to fall about 68% by 2030 — from 0.53 in 2025 to a central estimate of 0.17 (95% range 0.00–1.8). A 5-year backtest shows a typical error of ±354.3%, with 100% of held-out values landing inside the 95% band.

-68%Change by 2030TrendPercent 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 →
0.17Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–1.895% 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 →
±354.3%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, American Coot in Coastal California is projected to fall about 68% by 2030 — from 0.53 in 2025 to a central estimate of 0.17 (95% range 0.00–1.8). A 5-year backtest shows a typical error of ±354.3%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20260.300.001.9
20270.260.001.9
20280.230.001.8
20290.200.001.8
20300.170.001.8

Routes In Coastal California

Routes recording American Coot 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 →
Carrizo PlnCALIFORNIA881978
Cp. PendletonCALIFORNIA451991
Big BearCALIFORNIA161986
CoyoteCALIFORNIA132025
AthloneCALIFORNIA101989
CollegevilleCALIFORNIA81987
Green ValleyCALIFORNIA82012
VentucopaCALIFORNIA71997
GlennCALIFORNIA72015
Mesa GrandeCALIFORNIA62005
PescaderoCALIFORNIA52024
PolomaCALIFORNIA52023
Jofegan 2CALIFORNIA52025
RumseyCALIFORNIA41988
Tres PinosCALIFORNIA42002
Foster ParkCALIFORNIA41994
Lake HemetCALIFORNIA41981
Mark WestCALIFORNIA41978
CopperopolisCALIFORNIA42018
Harbor LakeCALIFORNIA31991
MorenoCALIFORNIA32024
El ToroCALIFORNIA31980
SisquocCALIFORNIA31975
ShafterCALIFORNIA31989
TehamaCALIFORNIA31997

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.