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Species · BCR 10 · BBS 2026 Release · 1966–2025

California Gull In Northern Rockies

All regionsNorthern RockiesWetland birds

California Gull in Northern Rockies has edged up: up 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 →
63Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 Northern Rockies. See the full index history below.

California Gull In Northern Rockies Population Forecast

If the recent trend holds, California Gull in Northern Rockies is projected to rise about 18× by 2030 — from 0.50 in 2025 to a central estimate of 8.8 (95% range 0.00–20). A 5-year backtest shows a typical error of ±664.6%, with 100% of held-out values landing inside the 95% band.

18×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 →
8.8Projected 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 →
0.00–2095% 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 →
±664.6%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 Northern Rockies is projected to rise about 18× by 2030 — from 0.50 in 2025 to a central estimate of 8.8 (95% range 0.00–20). A 5-year backtest shows a typical error of ±664.6%, 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 →
20268.30.0019
20278.40.0020
20288.50.0020
20298.60.0020
20308.80.0020

Routes In Northern Rockies

Routes recording California Gull in Northern Rockies.
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 →
Neponset ResUTAH6862018
CascadeIDAHO1201984
Saleratus CrUTAH1082018
Rock RiverWYOMING402022
MidvaleWYOMING292025
Hayden ValWYOMING251986
SeedskadeeWYOMING222014
RandolphUTAH152025
PathfinderWYOMING122025
WilsonWYOMING101985
LimaMONTANA72004
HarmonyWYOMING72022
BeaverheadMONTANA62005
AlturasIDAHO51969
KalispellMONTANA52003
Pablo Res.MONTANA52025
BridgeportOREGON51988
E. Bear LakeUTAH52012
CodyWYOMING52018
DuboisWYOMING51983
St MaryMONTANA41991
EtheteWYOMING42025
Sand DrawWYOMING42016
PolsonMONTANA32010
BoulderMONTANA32017

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