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

Herring Gull Population Trend in Indiana

All statesWetland birds

Herring Gull in Indiana has surged: up 142% on the route-weighted index since 1993.

+142%Since 1993TrendPercent 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 →
19YearsYears 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 IndianaNotable 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 →

Herring Gull has surged in Indiana: up 142% on the route-weighted index since 1993.

Herring Gull Population Forecast in Indiana

If the recent trend holds, Herring Gull in Indiana is projected to fall about 63% by 2027 — from 0.33 in 2022 to a central estimate of 0.12 (95% range 0.00–0.45). A 5-year backtest shows a typical error of ±123.5%, with 100% of held-out values landing inside the 95% band.

-63%Change by 2027TrendPercent 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 →
0.12Projected 2027 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.4595% 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 →
±123.5%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, Herring Gull in Indiana is projected to fall about 63% by 2027 — from 0.33 in 2022 to a central estimate of 0.12 (95% range 0.00–0.45). A 5-year backtest shows a typical error of ±123.5%, with 100% of held-out values landing inside the 95% band.19872027
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 →
20230.120.000.45
20240.120.000.45
20250.120.000.45
20260.120.000.45
20270.120.000.45

Herring Gull Survey Routes in Indiana

Routes recording Herring Gull in Indiana.
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 →
Indiana Dune1720221993
Gary219991987
Portage120042004
Kankakee Sands120042004
Portage 2120112011

Herring Gull Population Trend in Other States

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

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