BirdAnalyst
Species · Idaho · BBS 2025 Release · 1966–2024

Ring-billed Gull Population Trend in Idaho

All statesWetland birds

Ring-billed Gull in Idaho has collapsed: down 76% on the route-weighted index since 1971.

-76%Since 1971TrendPercent 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 →
31Routes 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 Ring-billed 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 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 →

Ring-billed Gull has collapsed in Idaho: down 76% on the route-weighted index since 1971.

Ring-billed Gull Population Forecast in Idaho

If the recent trend holds, Ring-billed Gull in Idaho is projected to rise about 106% by 2029 — from 2.6 in 2024 to a central estimate of 5.3 (95% range 0.00–21). A 5-year backtest shows a typical error of ±69.7%, with 100% of held-out values landing inside the 95% band.

+106%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 →
5.3Projected 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 →
0.00–2195% 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 →
±69.7%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, Ring-billed Gull in Idaho is projected to rise about 106% by 2029 — from 2.6 in 2024 to a central estimate of 5.3 (95% range 0.00–21). A 5-year backtest shows a typical error of ±69.7%, 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 →
20255.50.0021
20265.50.0021
20275.40.0021
20285.40.0021
20295.30.0021

Ring-billed Gull Survey Routes in Idaho

Routes recording Ring-billed 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 →
Blacks Creek27320171968
Mora5920242018
Picabo5420211988
Henry3719811973
Cabarton2919861986
Pocatello2420131979
Dubois2120081973
Pasadena Val1820151987
Squirrel1220142014
Glenns Ferry1019861985
Iron Springs820152007
Acequia719961988
Cascade619761968
Cedar Hill620241989
Gifford319931986
Craters319831983
Featherville320221989
Twin Buttes220051989
Triangle219921992
Crane Creek220151994
Daniels Res219901990
Blackft Res120101986
Mivoden120141983
Tractor Flat119881987
Baker120142014

Ring-billed Gull Population Trend in Other States

alabamaarizonacaliforniacoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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