BirdAnalyst
Species · Wyoming · BBS 2026 Release · 1966–2025

California Gull Population Trend in Wyoming

All statesWetland birds

California Gull in Wyoming has declined: down 41% on the route-weighted index since 1970.

-41%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 →
55YearsYears 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 166% by 2030 — from 0.55 in 2025 to a central estimate of 1.5 (95% range 0.00–4.7). A 5-year backtest shows a typical error of ±186.6%, with 100% of held-out values landing inside the 95% band.

+166%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 →
1.5Projected 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 →
0.00–4.795% 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 →
±186.6%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 166% by 2030 — from 0.55 in 2025 to a central estimate of 1.5 (95% range 0.00–4.7). A 5-year backtest shows a typical error of ±186.6%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20261.50.004.7
20271.50.004.7
20281.50.004.7
20291.50.004.7
20301.50.004.7

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
Midvale2920251974
Hayden Val2519861985
Seedskadee2220142001
Pathfinder1220251982
Wilson1019851982
Natrona719921984
Harmony720221980
Bucknum620001993
Cody520181989
Dubois519831983
Yoder420122000
Ethete420251992
Teapot Dome419831983
Sand Draw420161993
Yellowstone220251987
Prior Flats220222005
Fontenelle220251982
Buford220011977
Upton220221988
Rawlins220061988
Sybille Cyn219991980
Colter Bay119991968
Nowood120242024
Elk Horn120012001

California Gull Population Trend in Other States

alaskacaliforniacoloradoidahominnesotamontananevadanew-mexiconorth-dakotaoregonsouth-dakotautahwashington

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