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

Ring-billed Gull Population Trend in Maine

All statesWetland birds

Ring-billed Gull in Maine has risen sharply: up 73% on the route-weighted index since 1987.

+73%Since 1987TrendPercent 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 →
22Routes 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 →
38YearsYears 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 MaineNotable 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 risen sharply in Maine: up 73% on the route-weighted index since 1987.

Ring-billed Gull Population Forecast in Maine

If the recent trend holds, Ring-billed Gull in Maine is projected to rise about 12× by 2029 — from 0.05 in 2024 to a central estimate of 0.61 (95% range 0.00–1.6). A 5-year backtest shows a typical error of ±204.5%, with 100% of held-out values landing inside the 95% band.

12×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 →
0.61Projected 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 →
0.00–1.695% 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 →
±204.5%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 Maine is projected to rise about 12× by 2029 — from 0.05 in 2024 to a central estimate of 0.61 (95% range 0.00–1.6). A 5-year backtest shows a typical error of ±204.5%, with 100% of held-out values landing inside the 95% band.19852029
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 →
20250.610.001.6
20260.610.001.6
20270.610.001.6
20280.610.001.6
20290.610.001.6

Ring-billed Gull Survey Routes in Maine

Routes recording Ring-billed Gull in Maine.
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 →
Newcastle1020231985
Harmony1020152004
Carrabassett920232023
Greenville820221994
Deblois620071999
St David420052004
Otisfield Gr320112005
Seboomook Lk320121997
Wilson Mills220231991
Greenwood220142014
Brooks220172017
Moose River220072000
Washburn220042004
Boundary220152015
Westbrook120071987
Kittery Pt120241993
Turner119881988
East Troy120172017
Baker Lake 2120132013
Cambridge119981998
Medway120181998
Horse Mtn120082008

Ring-billed Gull Population Trend in Other States

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

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