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Species · BCR 2 · BBS 2026 Release · 1966–2025

Pigeon Guillemot In BCR 2

All regionsBCR 2Seabirds

Pigeon Guillemot in BCR 2 has declined: down 46% on the route-weighted index since 1987.

-46%Since 1987TrendPercent 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 →
4Routes 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 →
36YearsYears 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 Pigeon Guillemot in BCR 2. See the full index history below.

Pigeon Guillemot In BCR 2 Population Forecast

If the recent trend holds, Pigeon Guillemot in BCR 2 is projected to fall about 59% by 2030 — from 1.0 in 2025 to a central estimate of 0.41 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±36.4%, with 100% of held-out values landing inside the 95% band.

-59%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 →
0.41Projected 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 →
0.00–2.195% 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 →
±36.4%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, Pigeon Guillemot in BCR 2 is projected to fall about 59% by 2030 — from 1.0 in 2025 to a central estimate of 0.41 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±36.4%, with 100% of held-out values landing inside the 95% band.19852030
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 →
20260.560.002.2
20270.520.002.2
20280.480.002.2
20290.450.002.1
20300.410.002.1

Routes In BCR 2

Routes recording Pigeon Guillemot in BCR 2.
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 →
Kodiak 2ALASKA62025
Cold Bay (Short)ALASKA31991
Cold BayALASKA22007
ChiniakALASKA12024

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