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Species · Alabama · BBS 2025 Release · 1966–2024

Herring Gull Population Trend in Alabama

All statesWetland birds

Herring Gull in Alabama has collapsed: down 76% on the route-weighted index since 1972.

-76%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 →
5Routes 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 →
20YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Herring Gull Trends in AlabamaNotable 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 →

Herring Gull has collapsed in Alabama: down 76% on the route-weighted index since 1972.

Herring Gull Population Forecast in Alabama

If the recent trend holds, Herring Gull in Alabama is projected to stay roughly flat through 2017, near 0.01 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±86.8%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2017TrendPercent 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 →
0.01Projected 2017 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.0895% 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 →
±86.8%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, Herring Gull in Alabama is projected to stay roughly flat through 2017, near 0.01 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±86.8%, with 100% of held-out values landing inside the 95% band.19662017
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 →
20130.010.000.09
20140.010.000.08
20150.010.000.08
20160.010.000.08
20170.010.000.08

Herring Gull Survey Routes in Alabama

Routes recording Herring Gull in Alabama.
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 →
Dauphin Is 2220001991
Pine Grove119661966
Alabama Pt119961972
Dauphin Is119901970
Alabama Pt 2120122007

Herring Gull Population Trend in Other States

alaskacaliforniacoloradoconnecticutdelawarefloridaidahoillinoisindianakansaslouisianamainemarylandmassachusettsmichiganminnesotamontananew-hampshirenew-jerseynew-yorknorth-carolinaohiooregonpennsylvaniarhode-islandsouth-carolinatexasvermontvirginiawashingtonwest-virginiawisconsin

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