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Species · Alaska · BBS 2025 Release · 1966–2024

Common Eider Population Trend in Alaska

All statesWaterfowl

Common Eider in Alaska has risen sharply: up 69% on the route-weighted index since 1986.

+69%Since 1986TrendPercent 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 →
7Routes 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 →
27YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Common Eider Trends in AlaskaNotable 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 →

Common Eider has risen sharply in Alaska: up 69% on the route-weighted index since 1986.

Common Eider Population Forecast in Alaska

If the recent trend holds, Common Eider in Alaska is projected to rise about 434% by 2029 — from 0.24 in 2024 to a central estimate of 1.3 (95% range 0.00–2.6). A 5-year backtest shows a typical error of ±302.6%, with 60% of held-out values landing inside the 95% band.

+434%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 →
0.00–2.695% 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 →
±302.6%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, Common Eider in Alaska is projected to rise about 434% by 2029 — from 0.24 in 2024 to a central estimate of 1.3 (95% range 0.00–2.6). A 5-year backtest shows a typical error of ±302.6%, with 60% of held-out values landing inside the 95% band.19822029
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 →
20251.20.002.5
20261.20.002.5
20271.20.002.6
20281.30.002.6
20291.30.002.6

Common Eider Survey Routes in Alaska

Routes recording Common Eider in Alaska.
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 22220091986
Cape Nome1620241993
Kotzebue1520102008
Homer1219821982
Kuiu Island220042004
Council220231994
Kodiak119831983

Common Eider Population Trend in Other States

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