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Species · Maryland · BBS 2025 Release · 1966–2024

Ring-billed Gull Population Trend in Maryland

All statesWetland birds

Ring-billed Gull in Maryland has surged: up 11× on the route-weighted index since 1968.

11×Since 1968TrendPercent 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 →
28Routes 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 →
45YearsYears 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 MarylandNotable 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 Maryland: up 11× on the route-weighted index since 1968.

Ring-billed Gull Population Forecast in Maryland

If the recent trend holds, Ring-billed Gull in Maryland is projected to fall about 59% by 2022 — from 3.5 in 2017 to a central estimate of 1.5 (95% range 0.00–4.1). A 5-year backtest shows a typical error of ±1630.2%, with 80% of held-out values landing inside the 95% band.

-59%Change by 2022TrendPercent 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 →
1.5Projected 2022 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–4.195% 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 →
±1630.2%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 Maryland is projected to fall about 59% by 2022 — from 3.5 in 2017 to a central estimate of 1.5 (95% range 0.00–4.1). A 5-year backtest shows a typical error of ±1630.2%, with 80% of held-out values landing inside the 95% band.19662022
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 →
20181.40.004.0
20191.40.004.0
20201.40.004.1
20211.40.004.1
20221.50.004.1

Ring-billed Gull Survey Routes in Maryland

Routes recording Ring-billed Gull in Maryland.
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 →
Piney Neck16920171993
Newark10019841979
Theodore3419701970
Easton3220051997
Indiantown1319991997
Northeast820021972
Walnut620051999
Mardela520071972
Williamsport419841984
Berlin420161984
Melitota320171966
Emmitsburg219901990
Jones219921966
Golden Hill220051981
Madison220001987
Sinepuxent219781967
Steyer220002000
Severna Park219971995
Vindex119831983
Upper Xrds120071986
Beltsville119961996
Tall Timbers119991972
Elkton120171966
Matthews120081997
Honga120021994

Ring-billed Gull Population Trend in Other States

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

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