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Species · California · BBS 2025 Release · 1966–2024

California Gull Population Trend in California

All statesWetland birds

California Gull in California has increased: up 26% on the route-weighted index since 1973.

+26%Since 1973TrendPercent 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 →
58Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
53YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable California Gull Trends in CaliforniaNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for California Gull in California. See the full index history below.

California Gull Population Forecast in California

If the recent trend holds, California Gull in California is projected to rise about 206% by 2029 — from 0.63 in 2024 to a central estimate of 1.9 (95% range 0.00–5.1). A 5-year backtest shows a typical error of ±2037.8%, with 80% of held-out values landing inside the 95% band.

+206%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 →
1.9Projected 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 →
0.00–5.195% 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 →
±2037.8%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, California Gull in California is projected to rise about 206% by 2029 — from 0.63 in 2024 to a central estimate of 1.9 (95% range 0.00–5.1). A 5-year backtest shows a typical error of ±2037.8%, with 80% 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 →
20252.00.005.2
20262.00.005.2
20272.00.005.2
20282.00.005.1
20291.90.005.1

California Gull Survey Routes in California

Routes recording California Gull in 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 →
Bridgeport24519771972
Iron Gate9320191988
Goumaz8020042004
Likely5820171973
Haiwee Res5020041993
Crowley Lake4520241972
Poway3719801977
Cedarville3219781975
Dorris3120191972
Honeydew1620171977
Tuolumne Grove1519791979
Bodie1420161982
Oneals1020091999
San Ysidro919901987
Westley820172017
Benton820241975
Pennington619951995
Davis Creek619851981
Fairfax620181978
Mt Shasta519931980
Carrizo Pln419781978
Macdoel320191972
Coyote320241975
Ingalls319991973
Ravendale319991973

California Gull Population Trend in Other States

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