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Species · Alaska · BBS 2025 Release · 1966–2024

Common Merganser Population Trend in Alaska

All statesWaterfowl

Common Merganser in Alaska has collapsed: down 87% on the route-weighted index since 1983.

-87%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 →
52Routes 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 →
42YearsYears 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 Merganser 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 →

Common Merganser has collapsed in Alaska: down 87% on the route-weighted index since 1983.

Common Merganser Population Forecast in Alaska

If the recent trend holds, Common Merganser in Alaska is projected to fall about 100% by 2029 — from 0.42 in 2024 to a central estimate of 0.00 (95% range 0.00–3.6). A 5-year backtest shows a typical error of ±79.2%, 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 →
0.00–3.695% 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 →
±79.2%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 Merganser in Alaska is projected to fall about 100% by 2029 — from 0.42 in 2024 to a central estimate of 0.00 (95% range 0.00–3.6). A 5-year backtest shows a typical error of ±79.2%, 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 →
20250.140.003.7
20260.100.003.7
20270.070.003.7
20280.030.003.6
20290.000.003.6

Common Merganser Survey Routes in Alaska

Routes recording Common Merganser 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 →
Katmai N.P.2220052005
Cold Bay (Short)1819841984
Copper River1220111995
Anvik River820241999
Kodiak 2620242008
Salmon Lake520192019
Burma Road420091997
Goodnews Bay420042004
Ketchikan320012001
Unalakleet River320241998
Ft. Richrdsn320002000
Togiak River320051994
Sitka (Short)319921986
Hyder320071998
Circle220222011
Chatanika R220231992
Chistochina220082008
Monahan220102010
Juneau219891989
Council220192000
Kanuti Canyn220241993
Skagway220211994
Zarembo220101996
Petersville220031992
Kanektok Riv220031999

Common Merganser Population Trend in Other States

arizonacaliforniacoloradoconnecticutidahomainemarylandmassachusettsmichiganminnesotamontananevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-dakotaohiooregonpennsylvaniasouth-dakotautahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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