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

Franklin's Gull In Great Basin

All regionsGreat BasinWetland birds

Franklin's Gull in Great Basin has surged: up 153% on the route-weighted index since 1972.

+153%Since 1972TrendPercent 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 →
39Routes 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 →
52YearsYears 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 →

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 →

Franklin's Gull has surged in Great Basin: up 153% on the route-weighted index since 1972.

Franklin's Gull In Great Basin Population Forecast

If the recent trend holds, Franklin's Gull in Great Basin is projected to rise about 31% by 2029 — from 5.7 in 2024 to a central estimate of 7.4 (95% range 0.24–15). A 5-year backtest shows a typical error of ±20%, with 100% of held-out values landing inside the 95% band.

+31%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 →
7.4Projected 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 →
0.24–1595% 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 →
±20%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, Franklin's Gull in Great Basin is projected to rise about 31% by 2029 — from 5.7 in 2024 to a central estimate of 7.4 (95% range 0.24–15). A 5-year backtest shows a typical error of ±20%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20257.00.0014
20267.10.0014
20277.20.0814
20287.30.1614
20297.40.2415

Routes In Great Basin

Routes recording Franklin's 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 →
PromontoryUTAH7412024
PrestonIDAHO3782023
Bear RiverUTAH3042023
HenryIDAHO1161981
Blacks CreekIDAHO942015
Harney LakeOREGON752022
Cedar HillIDAHO612015
Tractor FlatIDAHO442024
DeltaUTAH432004
RirieIDAHO402019
Malheur NwrOREGON322022
Johnson CanUTAH301992
Modoc PointOREGON132009
PrincetonOREGON131985
Mud LakeIDAHO112023
LakeviewOREGON112022
BakerIDAHO71984
PocatelloIDAHO62015
Fish LakeOREGON62022
Warner VallyOREGON52023
Pasadena ValIDAHO41993
Catlow RimOREGON32024
ChinchaloOREGON32016
SpringfieldIDAHO22018
Daniels ResIDAHO22017

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