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Species · Utah · BBS 2025 Release · 1966–2024

California Gull Population Trend in Utah

All statesWetland birds

California Gull in Utah has surged: up 299% on the route-weighted index since 1970.

+299%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 →
54YearsYears 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 299% 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 stay roughly flat through 2029, near 29 (95% range 0.00–66). A 5-year backtest shows a typical error of ±169.7%, with 100% of held-out values landing inside the 95% band.

-10%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 →
29Projected 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 →
0.00–6695% 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 →
±169.7%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 stay roughly flat through 2029, near 29 (95% range 0.00–66). A 5-year backtest shows a typical error of ±169.7%, with 100% 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 →
2025280.0065
2026280.0065
2027290.0066
2028290.0066
2029290.0066

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 →
Goshen102920241968
Neponset Res68620181995
Woodruff62620242004
Johnson Can59820211987
Kamas19820241997
Saleratus Cr10820181995
Bear River9320231992
Pine Creek9019991999
Oak City5420061972
Promontory1620241969
Snowville1620241999
Timpie Spg1420031988
Fairfield620242006
Beck519871986
E. Bear Lake520121999
Beck 2519901990
Ferron520092007
Randolph320231992
Dixie Nf219941994
Wendover119871987
Lost Cr. Res120171995
Crawford Mts120232013
Beaver119811981
Navajo Lake120191969
Aneth120072007

California Gull Population Trend in Other States

alaskacaliforniacoloradoidahominnesotamontananevadanew-mexiconorth-dakotaoregonsouth-dakotawashingtonwyoming

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