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Species · Utah · BBS 2026 Release · 1966–2025

California Gull Population Trend in Utah

All statesWetland birds

California Gull in Utah has surged: up 216% on the route-weighted index since 1970.

+216%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 →
34Routes 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 →
55YearsYears 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 UtahNotable 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 increasecomputed 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 →

California Gull has surged in Utah: up 216% on the route-weighted index since 1970.

California Gull Population Forecast in Utah

If the recent trend holds, California Gull in Utah is projected to rise about 352% by 2030 — from 6.1 in 2025 to a central estimate of 28 (95% range 0.00–65). A 5-year backtest shows a typical error of ±139.9%, with 100% of held-out values landing inside the 95% band.

+352%Change by 2030TrendPercent 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 →
28Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–6595% 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 →
±139.9%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 Utah is projected to rise about 352% by 2030 — from 6.1 in 2025 to a central estimate of 28 (95% range 0.00–65). A 5-year backtest shows a typical error of ±139.9%, with 100% of held-out values landing inside the 95% band.19682030
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 →
2026270.0064
2027270.0064
2028270.0064
2029270.0065
2030280.0065

California Gull Survey Routes in Utah

Routes recording California Gull in Utah.
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 →
Neponset Res68620181995
Johnson Can59820211987
Bear River19320251992
Kamas14020251997
Saleratus Cr10820181995
Pine Creek9019991999
Oak City5420061972
Goshen4520251968
Randolph1520251992
Timpie Spg1420031988
Grantsville1220252001
Fairfield620242006
Promontory520251969
Beck519871986
E. Bear Lake520121999
Beck 2519901990
Ferron520092007
Callao220252003
Dixie Nf219941994
Snowville220251999
Wendover119871987
Lost Cr. Res120171995
Woodruff120252004
Crawford Mts120232013
Beaver119811981

California Gull Population Trend in Other States

alaskacaliforniacoloradoidahominnesotamontananevadanew-mexiconorth-dakotaoregonsouth-dakotawashingtonwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.