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Species · Wyoming · BBS 2025 Release · 1966–2024

California Gull Population Trend in Wyoming

All statesWetland birds

California Gull in Wyoming has edged down: down 11% on the route-weighted index since 1970.

-11%Since 1970TrendPercent 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 →
46Routes 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 →
54YearsYears 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 WyomingNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for California Gull in Wyoming. See the full index history below.

California Gull Population Forecast in Wyoming

If the recent trend holds, California Gull in Wyoming is projected to rise about 224% by 2029 — from 0.48 in 2024 to a central estimate of 1.6 (95% range 0.00–4.8). A 5-year backtest shows a typical error of ±449%, with 100% of held-out values landing inside the 95% band.

+224%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 →
1.6Projected 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 →
0.00–4.895% 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 →
±449%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 Wyoming is projected to rise about 224% by 2029 — from 0.48 in 2024 to a central estimate of 1.6 (95% range 0.00–4.8). A 5-year backtest shows a typical error of ±449%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20251.60.004.8
20261.60.004.8
20271.60.004.8
20281.60.004.8
20291.60.004.8

California Gull Survey Routes in Wyoming

Routes recording California Gull in Wyoming.
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 →
Rock River4020221990
Ethete3820241992
Fontenelle3420221982
Hayden Val2519861985
Seedskadee2220142001
Wilson1019851982
Natrona719921984
Harmony720221980
Dwyer620191992
Bucknum620001993
Cody520181989
Dubois519831983
Yoder420122000
Teapot Dome419831983
Sand Draw420161993
Pathfinder320231982
Flamin Gorge320231988
Prior Flats220222005
Midvale220241974
Buford220011977
Upton220221988
Rawlins220061988
Sybille Cyn219991980
Yellowstone120211987
Colter Bay119991968

California Gull Population Trend in Other States

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