BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Pigeon Guillemot

AlcidaeSeabirdsCepphus columba

Pigeon Guillemot has edged up: up 17% on the route-weighted index since 1973.

+17%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 →
28RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
53Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Pigeon Guillemot

The Pigeon Guillemot (Cepphus columba) is a North American member of the Auks, Murres & Puffins (Alcidae). In this analysis it is grouped with the seabirds.

Size
8–17.5 in long (20–45 cm) — a compact seabird (typical for the family)
Habitat
Open ocean and coastlines, coming ashore mainly to nest in colonies.
Diet
Fish, squid and other marine animals caught at or below the surface.
Range
Recorded on 28 Breeding Bird Survey routes across 4 states, most concentrated in the Northern Pacific Rainforest.
Family
Alcidae · Seabirds

Notable Pigeon Guillemot TrendsNotable 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. See the full index history below.

Pigeon Guillemot Population Forecast

If the recent trend holds, Pigeon Guillemot is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.02). A 5-year backtest shows a typical error of ±63.1%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.01Projected 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 →
0.00–0.0295% 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 →
±63.1%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 is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.02). A 5-year backtest shows a typical error of ±63.1%, with 100% of held-out values landing inside the 95% band.19702029
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 →
20250.010.000.02
20260.010.000.02
20270.010.000.02
20280.010.000.02
20290.010.000.02

Where the Pigeon Guillemot Is Detected

BBS routes recording Pigeon Guillemot, sized by most recent count.

Pigeon Guillemot Population Trend by State

Pigeon Guillemot population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Alaska-49%198512
California-87%19757
Oregoninsufficient datan/a1
Washington-69%19738

Pigeon Guillemot Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Pigeon Guillemot population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
BCR 2-61%19874
Northern Pacific Rainforest-23%197321

Pigeon Guillemot Conservation Status

Our route-weighted index shows it up about 17% since 1973.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.