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

Red-winged Blackbird In Coastal California

All regionsCoastal CaliforniaGeneralists

Red-winged Blackbird in Coastal California has fallen sharply: down 52% on the route-weighted index since 1970.

-52%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 →
115Routes 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 →
56YearsYears 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 →

Red-winged Blackbird has fallen sharply in Coastal California: down 52% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Red-winged Blackbird in Coastal California is projected to rise about 61% by 2029 — from 25 in 2024 to a central estimate of 40 (95% range 0.00–94). A 5-year backtest shows a typical error of ±49.6%, with 100% of held-out values landing inside the 95% band.

+61%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 →
40Projected 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 →
0.00–9495% 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 →
±49.6%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, Red-winged Blackbird in Coastal California is projected to rise about 61% by 2029 — from 25 in 2024 to a central estimate of 40 (95% range 0.00–94). A 5-year backtest shows a typical error of ±49.6%, with 100% of held-out values landing inside the 95% band.19682029
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 →
2025440.0098
2026430.0097
2027420.0096
2028410.0095
2029400.0094

Routes In Coastal California

Routes recording Red-winged Blackbird 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 →
GlennCALIFORNIA7782023
AthloneCALIFORNIA3562007
AtwaterCALIFORNIA3432012
Buena VistaCALIFORNIA3032019
Tres PinosCALIFORNIA2662003
Collegeville 2CALIFORNIA2652023
ZamoraCALIFORNIA1742024
Staten Is.CALIFORNIA1542024
JofeganCALIFORNIA1522023
HollisterCALIFORNIA1462011
LivermoreCALIFORNIA1461991
Ora LomaCALIFORNIA1272024
ReddingCALIFORNIA1191983
CollegevilleCALIFORNIA1002004
TranquillityCALIFORNIA962024
OrlandCALIFORNIA922022
PowayCALIFORNIA751980
CaruthersCALIFORNIA731987
PenningtonCALIFORNIA712024
ShafterCALIFORNIA691989
LockwoodCALIFORNIA602024
ColmaCALIFORNIA581972
Hollister 2CALIFORNIA582024
RumseyCALIFORNIA562008
TiptonCALIFORNIA481997

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