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Species · Idaho · BBS 2025 Release · 1966–2024

Franklin's Gull Population Trend in Idaho

All statesWetland birds

Franklin's Gull in Idaho has surged: up 761% on the route-weighted index since 1972.

+761%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 →
19Routes 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 →
51YearsYears 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 IdahoNotable 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 →

Franklin's Gull has surged in Idaho: up 761% on the route-weighted index since 1972.

Franklin's Gull Population Forecast in Idaho

If the recent trend holds, Franklin's Gull in Idaho is projected to rise about 933% by 2029 — from 1.8 in 2024 to a central estimate of 19 (95% range 0.00–40). A 5-year backtest shows a typical error of ±169.9%, with 80% of held-out values landing inside the 95% band.

+933%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 →
19Projected 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 →
0.00–4095% 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 →
±169.9%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, Franklin's Gull in Idaho is projected to rise about 933% by 2029 — from 1.8 in 2024 to a central estimate of 19 (95% range 0.00–40). A 5-year backtest shows a typical error of ±169.9%, with 80% of held-out values landing inside the 95% band.19692029
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 →
2025180.0039
2026180.0039
2027190.0039
2028190.0039
2029190.0040

Franklin's Gull Survey Routes in Idaho

Routes recording Franklin's Gull in Idaho.
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 →
Preston37820231988
Henry11619811973
Blacks Creek9420151995
Cedar Hill6120152014
Tractor Flat4420241988
Ririe4020191971
Mud Lake1120231988
Baker719841978
Pocatello620151980
Pasadena Val419931993
Kyle Canyon220242003
Springfield220181969
Featherville220132013
Daniels Res220172017
Blackft Res120181985
Twin Buttes120172010
Lost River120162016
Circular Bu120231988
Dubois120021988

Franklin's Gull Population Trend in Other States

californiakansasminnesotamontananebraskanorth-dakotaoregonsouth-dakotautahwyoming

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