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Species · Washington · BBS 2026 Release · 1966–2025

Pigeon Guillemot Population Trend in Washington

All statesSeabirds

Pigeon Guillemot in Washington has declined: down 48% on the route-weighted index since 1973.

-48%Since 1973TrendPercent 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 →
8Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
48YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Pigeon Guillemot Trends in WashingtonNotable 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 Washington. See the full index history below.

Pigeon Guillemot Population Forecast in Washington

If the recent trend holds, Pigeon Guillemot in Washington is projected to fall about 84% by 2030 — from 0.21 in 2025 to a central estimate of 0.03 (95% range 0.00–0.27). A 5-year backtest shows a typical error of ±66.9%, with 100% of held-out values landing inside the 95% band.

-84%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 →
0.03Projected 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 →
0.00–0.2795% 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 →
±66.9%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 Washington is projected to fall about 84% by 2030 — from 0.21 in 2025 to a central estimate of 0.03 (95% range 0.00–0.27). A 5-year backtest shows a typical error of ±66.9%, with 100% of held-out values landing inside the 95% band.19702030
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 →
20260.050.000.28
20270.040.000.28
20280.040.000.28
20290.040.000.27
20300.030.000.27

Pigeon Guillemot Survey Routes in Washington

Routes recording Pigeon Guillemot in Washington.
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 →
Deception1119981992
Port Angeles720251970
Ilwaco419931993
Ozette319831971
Mukilteo320252016
Warm Beach 2220242018
Warm Beach120161985
Vashon Is.120192000

Pigeon Guillemot Population Trend in Other States

alaskacaliforniaoregon

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