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Species · Utah · BBS 2026 Release · 1966–2025

Franklin's Gull Population Trend in Utah

All statesWetland birds

Franklin's Gull in Utah has fallen sharply: down 61% on the route-weighted index since 1972.

-61%Since 1972TrendPercent 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 →
13Routes 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 →
37YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Franklin's 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 declinecomputed 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 →

Franklin's Gull has fallen sharply in Utah: down 61% on the route-weighted index since 1972.

Franklin's Gull Population Forecast in Utah

If the recent trend holds, Franklin's Gull in Utah is projected to fall about 100% by 2030 — from 0.53 in 2025 to a central estimate of 0.00 (95% range 0.00–17). A 5-year backtest shows a typical error of ±788.4%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–1795% 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 →
±788.4%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, Franklin's Gull in Utah is projected to fall about 100% by 2030 — from 0.53 in 2025 to a central estimate of 0.00 (95% range 0.00–17). A 5-year backtest shows a typical error of ±788.4%, with 100% of held-out values landing inside the 95% band.19692030
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 →
20260.000.0017
20270.000.0017
20280.000.0017
20290.000.0017
20300.000.0017

Franklin's Gull Survey Routes in Utah

Routes recording Franklin's 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 →
Promontory74120241969
Delta4320041997
Saleratus Cr3920072007
Bear River3620251992
Johnson Can3019921992
Kamas320002000
Lost Cr. Res220002000
Crawford Mts220022002
Neponset Res120032001
Woodruff120242008
Snowville120162016
Randolph120211993
Callao120242006

Franklin's Gull Population Trend in Other States

californiacoloradoidahokansasminnesotamontananebraskanorth-dakotaoregonsouth-dakotawyoming

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