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Species · Alaska · BBS 2025 Release · 1966–2024

Harlequin Duck Population Trend in Alaska

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Harlequin Duck in Alaska has collapsed: down 76% on the route-weighted index since 1983.

-76%Since 1983TrendPercent 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 →
38Routes 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 →
43YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Harlequin Duck 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 declinecomputed 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 →

Harlequin Duck has collapsed in Alaska: down 76% on the route-weighted index since 1983.

Harlequin Duck Population Forecast in Alaska

If the recent trend holds, Harlequin Duck in Alaska is projected to fall about 100% by 2029 — from 0.22 in 2024 to a central estimate of 0.00 (95% range 0.00–1.6). A 5-year backtest shows a typical error of ±135.9%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–1.695% 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 →
±135.9%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, Harlequin Duck in Alaska is projected to fall about 100% by 2029 — from 0.22 in 2024 to a central estimate of 0.00 (95% range 0.00–1.6). A 5-year backtest shows a typical error of ±135.9%, 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 →
20250.000.001.6
20260.000.001.6
20270.000.001.6
20280.000.001.6
20290.000.001.6

Harlequin Duck Survey Routes in Alaska

Routes recording Harlequin Duck 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 →
Zarembo4720012001
Thorne Bay1819941993
Adak1620011983
Mitkof Isle1619951988
Sourdough1419941994
Chiniak1220231985
Skagway820241993
Thorne Bay 2820232023
Zimovia Strt720241988
Unalakleet River620231996
Cape Nome520181993
Salmon Lake520181994
Teller520181995
Sitka (Short)519921984
Juneau420231993
Petersburg419871987
Juneau Alt319851984
Stikine River220072007
Council220181994
Haines220221975
Nome220121999
Hyder220072003
Kotzebue220192019
Kodiak 2220211985
Savage220071994

Harlequin Duck Population Trend in Other States

californiaidahomontanaoregonwashingtonwyoming

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