BirdAnalyst
Species · Michigan · BBS 2025 Release · 1966–2024

Common Merganser Population Trend in Michigan

All statesWaterfowl

Common Merganser in Michigan has edged down: down 18% on the route-weighted index since 1981.

-18%Since 1981TrendPercent 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 →
26Routes 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 →
29YearsYears 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 MichiganNotable 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 Common Merganser in Michigan. See the full index history below.

Common Merganser Population Forecast in Michigan

If the recent trend holds, Common Merganser in Michigan is projected to stay roughly flat through 2029, near 0.04 (95% range 0.00–0.13). A 5-year backtest shows a typical error of ±217.7%, 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 →
0.04Projected 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 →
0.00–0.1395% 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 →
±217.7%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, Common Merganser in Michigan is projected to stay roughly flat through 2029, near 0.04 (95% range 0.00–0.13). A 5-year backtest shows a typical error of ±217.7%, with 100% of held-out values landing inside the 95% band.19782029
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 →
20250.040.000.13
20260.040.000.13
20270.040.000.13
20280.040.000.13
20290.040.000.13

Common Merganser Survey Routes in Michigan

Routes recording Common Merganser in Michigan.
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 →
Red Oak720112011
Hiawatha Nf420132007
Bergland219901985
Bear Lake220111992
Oberlin219941994
Sand Lake219961996
Harrietta120242024
Marenisco119941994
Ned Lake120141997
Herman120222004
Crystal Fls120092009
Gibbs City120131994
Maple Grove120172017
Ishpeming120212021
Imp Lake120042004
Wilson120082008
Cunard119971997
Muskallonge120131985
Gilchrist119971989
Lake City119781978
Skegemog Pt120232011
Raco120162001
Pickford120001979
Riggsville119901990
Cathro120162016

Common Merganser Population Trend in Other States

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

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