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

Common Gallinule In Coastal California

All regionsCoastal CaliforniaWetland birds

Common Gallinule in Coastal California has collapsed: down 86% on the route-weighted index since 1971.

-86%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 →
22Routes 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 →
46YearsYears 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 →

Common Gallinule has collapsed in Coastal California: down 86% on the route-weighted index since 1971.

Forecast

If the recent trend holds, Common Gallinule in Coastal California is projected to stay roughly flat through 2026, near 0.36 (95% range 0.00–0.71). A 5-year backtest shows a typical error of ±2478.6%, with 0% of held-out values landing inside the 95% band.

n/aChange by 2026TrendPercent 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 →
0.36Projected 2026 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.7195% 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 →
±2478.6%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, Common Gallinule in Coastal California is projected to stay roughly flat through 2026, near 0.36 (95% range 0.00–0.71). A 5-year backtest shows a typical error of ±2478.6%, with 0% of held-out values landing inside the 95% band.19692026
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 →
20220.340.000.69
20230.340.000.70
20240.350.000.70
20250.350.000.70
20260.360.000.71

Routes In Coastal California

Routes recording Common Gallinule 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 →
GlennCALIFORNIA122009
GravesboroCALIFORNIA41971
AuburnCALIFORNIA31975
BakersfieldCALIFORNIA21970
CoyoteCALIFORNIA21983
OnealsCALIFORNIA21979
PenningtonCALIFORNIA11988
CollegevilleCALIFORNIA11969
HollisterCALIFORNIA12007
Point ReyesCALIFORNIA12009
OrlandCALIFORNIA12003
OnoCALIFORNIA12011
FolsomCALIFORNIA12003
ArvinCALIFORNIA12012
CordovaCALIFORNIA11980
Gold HillCALIFORNIA11999
WestleyCALIFORNIA12015
TranquillityCALIFORNIA12003
LockwoodCALIFORNIA11983
ZamoraCALIFORNIA12021
Ora LomaCALIFORNIA11973
Buena VistaCALIFORNIA11993

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