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

Brewer's Blackbird In Coastal California

All regionsCoastal CaliforniaGeneralists

Brewer's Blackbird in Coastal California has collapsed: down 77% on the route-weighted index since 1970.

-77%Since 1970
118Routes In Region
56Years

Notable Signals

long arc declinecomputed index

Brewer's Blackbird has collapsed in Coastal California: down 77% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Brewer's Blackbird in Coastal California is projected to fall about 34% by 2029 — from 25 in 2024 to a central estimate of 17 (95% range 0.00–48). A 5-year backtest shows a typical error of ±10.5%, with 100% of held-out values landing inside the 95% band.

-34%Change by 2029
17Projected 2029 index
0.00–4895% range
±10.5%Backtest error
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 index95% low95% high
2025230.0054
2026220.0053
2027200.0051
2028180.0049
2029170.0048

Routes In Coastal California

Routes recording Brewer's Blackbird in Coastal California.
ReddingCALIFORNIA2791983
Buena VistaCALIFORNIA2082019
OilfieldsCALIFORNIA1902013
Collegeville 2CALIFORNIA1902023
GlennCALIFORNIA1852023
ColmaCALIFORNIA1751972
LivermoreCALIFORNIA1481991
CaruthersCALIFORNIA1291987
GravesboroCALIFORNIA1251995
ShafterCALIFORNIA1241989
ParkfieldCALIFORNIA1212024
HollisterCALIFORNIA1202011
Tres PinosCALIFORNIA1192003
Hollister 2CALIFORNIA1182024
GreenfieldCALIFORNIA1162024
AthloneCALIFORNIA982007
CollegevilleCALIFORNIA932004
South LakeCALIFORNIA872006
WestleyCALIFORNIA832024
Tres Pinos 2CALIFORNIA782011
RiovistaCALIFORNIA762024
TiptonCALIFORNIA741997
CordovaCALIFORNIA731981
OrlandCALIFORNIA682022
Big BearCALIFORNIA671986

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