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Species · Wisconsin · BBS 2025 Release · 1966–2024

Hooded Merganser Population Trend in Wisconsin

All statesWaterfowl

Hooded Merganser in Wisconsin has edged down: down 20% on the route-weighted index since 1968.

-20%Since 1968TrendPercent 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 →
51Routes 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 →
53YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Hooded Merganser Trends in WisconsinNotable 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 Hooded Merganser in Wisconsin. See the full index history below.

Hooded Merganser Population Forecast in Wisconsin

If the recent trend holds, Hooded Merganser in Wisconsin is projected to rise about 55% by 2029 — from 0.06 in 2024 to a central estimate of 0.10 (95% range 0.01–0.18). A 5-year backtest shows a typical error of ±84.7%, with 80% of held-out values landing inside the 95% band.

+55%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 →
0.10Projected 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 →
0.01–0.1895% 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 →
±84.7%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, Hooded Merganser in Wisconsin is projected to rise about 55% by 2029 — from 0.06 in 2024 to a central estimate of 0.10 (95% range 0.01–0.18). A 5-year backtest shows a typical error of ±84.7%, with 80% of held-out values landing inside the 95% band.19662029
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 →
20250.090.010.17
20260.090.010.17
20270.100.010.17
20280.100.010.18
20290.100.010.18

Hooded Merganser Survey Routes in Wisconsin

Routes recording Hooded Merganser in Wisconsin.
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 →
Elderon320232023
N Freedom320102010
Fall River319691969
Pt Washingtn319981998
Bayfield220152012
Dresser220241968
Omro 2220042004
Popple River220171971
Casco220082007
Flambeau220132009
Chaffey120112011
Iron River120042004
Minong120211975
Grand View120221972
Shanagolden120191980
Land O Lakes120021993
Hudson120242001
Union Twp120211986
Loraine120181997
Cumberland120061967
Weyerhauser120182015
Couderay120171969
Exeland120141970
Gilman120171975
Phillips120131968

Hooded Merganser Population Trend in Other States

alabamaalaskaarkansascoloradoconnecticutidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-yorknorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontwashingtonwest-virginiawyoming

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