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

Ring-billed Gull Population Trend in Vermont

All statesWetland birds

Ring-billed Gull in Vermont has surged: up 828% on the route-weighted index since 1969.

+828%Since 1969TrendPercent 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 →
12Routes 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 →
57YearsYears 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 VermontNotable 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 →

Ring-billed Gull has surged in Vermont: up 828% on the route-weighted index since 1969.

Ring-billed Gull Population Forecast in Vermont

If the recent trend holds, Ring-billed Gull in Vermont is projected to rise about 89% by 2029 — from 4.2 in 2024 to a central estimate of 7.9 (95% range 0.00–27). A 5-year backtest shows a typical error of ±1049.4%, with 100% of held-out values landing inside the 95% band.

+89%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 →
7.9Projected 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 →
0.00–2795% 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 →
±1049.4%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, Ring-billed Gull in Vermont is projected to rise about 89% by 2029 — from 4.2 in 2024 to a central estimate of 7.9 (95% range 0.00–27). A 5-year backtest shows a typical error of ±1049.4%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20258.00.0027
20268.00.0027
20278.00.0027
20287.90.0027
20297.90.0027

Ring-billed Gull Survey Routes in Vermont

Routes recording Ring-billed Gull in Vermont.
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 →
Grand Isle5720241968
Bristol3920181995
W Rutland3019711971
Hinesburg2219941966
Fletcher1120241968
Colchester720241986
Hardwick519861973
Greensboro519981977
Waterville419801973
Middlesex119991999
East Calais120021984
Stowe120071988

Ring-billed Gull Population Trend in Other States

alabamaarizonacaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatexasutahvirginiawashingtonwest-virginiawisconsinwyoming

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