BirdAnalyst
Species · North Dakota · BBS 2026 Release · 1966–2025

California Gull Population Trend in North Dakota

All statesWetland birds

California Gull in North Dakota has surged: up 730% on the route-weighted index since 1976.

+730%Since 1976TrendPercent 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 →
21Routes 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 →
50YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable California Gull Trends in North DakotaNotable 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 →

California Gull has surged in North Dakota: up 730% on the route-weighted index since 1976.

California Gull Population Forecast in North Dakota

If the recent trend holds, California Gull in North Dakota is projected to fall about 79% by 2030 — from 3.1 in 2025 to a central estimate of 0.67 (95% range 0.00–1.8). A 5-year backtest shows a typical error of ±71.4%, with 80% of held-out values landing inside the 95% band.

-79%Change by 2030TrendPercent 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 →
0.67Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–1.895% 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 →
±71.4%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, California Gull in North Dakota is projected to fall about 79% by 2030 — from 3.1 in 2025 to a central estimate of 0.67 (95% range 0.00–1.8). A 5-year backtest shows a typical error of ±71.4%, with 80% of held-out values landing inside the 95% band.19742030
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 →
20260.630.001.7
20270.640.001.8
20280.650.001.8
20290.660.001.8
20300.670.001.8

California Gull Survey Routes in North Dakota

Routes recording California Gull in North Dakota.
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 →
Douglas Crk8320251982
Buchanan820181975
Danzig620082008
Tobacco520061988
Regan320061978
Powers Lake320221995
Braddock320231992
Horsehead Lk220251980
Lakota 2220102010
Edgeley120152007
Lake George120081974
Lakota120051980
Niles119981996
Dunn Center120182011
Stanley119991981
Wild Rose120221982
Parshall119991982
Sheyenne Lk120231988
Turtle Mtns119881988
Montpelier120242005
Danzig 2120222021

California Gull Population Trend in Other States

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Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.