BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

California Gull In Great Basin

All regionsGreat BasinWetland birds

California Gull in Great Basin has held roughly steady: up 7% on the route-weighted index since 1970.

+7%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 →
109Routes 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 →
56YearsYears 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 Great Basin. See the full index history below.

Forecast

If the recent trend holds, California Gull in Great Basin is projected to fall about 15% by 2029 — from 9.6 in 2024 to a central estimate of 8.1 (95% range 0.00–18). A 5-year backtest shows a typical error of ±70.6%, with 100% of held-out values landing inside the 95% band.

-15%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 →
8.1Projected 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 →
0.00–1895% 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 →
±70.6%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 Great Basin is projected to fall about 15% by 2029 — from 9.6 in 2024 to a central estimate of 8.1 (95% range 0.00–18). A 5-year backtest shows a typical error of ±70.6%, 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 →
20258.60.0019
20268.50.0019
20278.40.0019
20288.20.0019
20298.10.0018

Routes In Great Basin

Routes recording California Gull in Great Basin.
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 →
GoshenUTAH10292024
Johnson CanUTAH5982021
MerrillOREGON2502022
BridgeportCALIFORNIA2451977
HenryIDAHO1231983
Ruby Valley 2NEVADA1182024
Iron GateCALIFORNIA932019
Bear RiverUTAH932023
Pine CreekUTAH901999
PotholesWASHINGTON712019
SpringfieldIDAHO652018
Sand PassNEVADA642019
LikelyCALIFORNIA582017
Oak CityUTAH542006
MercerWASHINGTON491985
KeystoneWASHINGTON482024
Crowley LakeCALIFORNIA452024
FallonNEVADA352024
CedarvilleCALIFORNIA321978
DorrisCALIFORNIA312019
PocatelloIDAHO302019
UmatillaOREGON292023
RonaldWASHINGTON291990
PrincetonOREGON251985
Blacks CreekIDAHO232015

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