BirdAnalyst
Species · BCR 4 · BBS 2025 Release · 1966–2024

Short-billed Gull In BCR 4

All regionsBCR 4Wetland birds

Short-billed Gull in BCR 4 has declined: down 37% on the route-weighted index since 1977.

-37%Since 1977TrendPercent 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 →
58Routes 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 →
45YearsYears 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 Short-billed Gull in BCR 4. See the full index history below.

Short-billed Gull In BCR 4 Population Forecast

If the recent trend holds, Short-billed Gull in BCR 4 is projected to rise about 98% by 2029 — from 0.64 in 2024 to a central estimate of 1.3 (95% range 0.00–4.5). A 5-year backtest shows a typical error of ±159.8%, with 100% of held-out values landing inside the 95% band.

+98%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 →
1.3Projected 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 →
0.00–4.595% 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 →
±159.8%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, Short-billed Gull in BCR 4 is projected to rise about 98% by 2029 — from 0.64 in 2024 to a central estimate of 1.3 (95% range 0.00–4.5). A 5-year backtest shows a typical error of ±159.8%, with 100% of held-out values landing inside the 95% band.19752029
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 →
20251.50.004.7
20261.40.004.7
20271.40.004.6
20281.30.004.6
20291.30.004.5

Routes In BCR 4

Routes recording Short-billed Gull in BCR 4.
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 →
KalifonskyALASKA562023
HomerALASKA391982
Kobuk River (Short)ALASKA221992
CottonwoodALASKA201990
WasillaALASKA101983
Tangle LakesALASKA101987
Anvik RiverALASKA102023
SavageALASKA62024
SlanaALASKA42022
ToklatALASKA42024
Seven LakesALASKA42015
Galena (Short)ALASKA42023
TonsinaALASKA32017
Lake LouiseALASKA32010
Nicholai SlALASKA32024
Porcupine R.ALASKA32002
KuskulanaALASKA31999
MonahanALASKA22019
CantwellALASKA22019
WillowALASKA22022
L SalchaALASKA22005
SourdoughALASKA22024
Bear CreekALASKA21991
CohoeALASKA22023
PetersvilleALASKA22024

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