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Species · California · BBS 2025 Release · 1966–2024

Brewer's Blackbird Population Trend in California

All statesGeneralists

Brewer's Blackbird in California has fallen sharply: down 70% on the route-weighted index since 1970.

-70%Since 1970
233Routes In State
56Years

Notable Brewer's Blackbird Trends in California

long arc declinecomputed index

Brewer's Blackbird has fallen sharply in California: down 70% on the route-weighted index since 1970.

Brewer's Blackbird Population Forecast in California

If the recent trend holds, Brewer's Blackbird in California is projected to fall about 42% by 2029 — from 28 in 2024 to a central estimate of 16 (95% range 0.00–32). A 5-year backtest shows a typical error of ±22.5%, with 100% of held-out values landing inside the 95% band.

-42%Change by 2029
16Projected 2029 index
0.00–3295% range
±22.5%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
2025203.836
2026192.935
2027181.934
2028170.9633
2029160.0032

Brewer's Blackbird Survey Routes in California

Routes recording Brewer's Blackbird in California.
Dorris64620191972
Likely50720241971
Cedarville32820241974
Redding27919831972
Buena Vista20820191990
Oilfields19020131968
Collegeville 219020232007
Glenn18520231971
Colma17519721968
Macdoel16020191972
Livermore14819911972
Sattley14320241972
Caruthers12919871972
Gravesboro12519951968
Shafter12419891971
Parkfield12120241968
Hollister12020111973
Tres Pinos11920031968
Hollister 211820242012
Greenfield11620241973
Nubieber11520181970
Yreka11020191973
Athlone9820071972
Crowley Lake9720241972
Gazelle9520211988

Brewer's Blackbird Population Trend in Other States

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