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Species · California · BBS 2025 Release · 1966–2024

Brandt's Cormorant Population Trend in California

All statesWetland birds

Brandt's Cormorant in California has surged: up 109% on the route-weighted index since 1972.

+109%Since 1972
10Routes In State
49Years

Notable Brandt's Cormorant Trends in California

long arc increasecomputed index

Brandt's Cormorant has surged in California: up 109% on the route-weighted index since 1972.

Brandt's Cormorant Population Forecast in California

If the recent trend holds, Brandt's Cormorant in California is projected to fall about 86% by 2029 — from 0.63 in 2024 to a central estimate of 0.09 (95% range 0.00–1.1). A 5-year backtest shows a typical error of ±94.6%, with 80% of held-out values landing inside the 95% band.

-86%Change by 2029
0.09Projected 2029 index
0.00–1.195% range
±94.6%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
20250.110.001.1
20260.110.001.1
20270.100.001.1
20280.100.001.1
20290.090.001.1

Brandt's Cormorant Survey Routes in California

Routes recording Brandt's Cormorant in California.
S Catalina13420192013
Harbor Lake 25920242014
Bodega Bay2320171974
Poway619801980
Harbor Lake419801978
Fish Rock320131973
Fairfax320171978
Navarro219801979
Crescent Cty119821982
Honeydew120171968

Brandt's Cormorant Population Trend in Other States

oregonwashington

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