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

Common Merganser Population Trend in Montana

All statesWaterfowl

Common Merganser in Montana has surged: up 313% on the route-weighted index since 1975.

+313%Since 1975
44Routes In State
49Years

Notable Common Merganser Trends in Montana

long arc increasecomputed index

Common Merganser has surged in Montana: up 313% on the route-weighted index since 1975.

Common Merganser Population Forecast in Montana

If the recent trend holds, Common Merganser in Montana is projected to stay roughly flat through 2029, near 0.25 (95% range 0.01–0.48). A 5-year backtest shows a typical error of ±46.5%, with 100% of held-out values landing inside the 95% band.

-9%Change by 2029
0.25Projected 2029 index
0.01–0.4895% range
±46.5%Backtest error
19722029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected index95% low95% high
20250.240.010.47
20260.240.010.48
20270.240.010.48
20280.250.010.48
20290.250.010.48

Common Merganser Survey Routes in Montana

Routes recording Common Merganser in Montana.
Ninemile1120241993
Beaverhead819971981
Kalispell620071981
Fish Creek620192003
Libby Dam520241979
Great Falls419951973
Flatwillow419771977
Red Rock419891975
Augusta319971986
Swan Lake320232021
Maynard Coulee320222022
Willow Creek 2220071983
St Xavier 2220182018
Circle220001997
Two Dot220241976
Thompson Riv220211996
Wheat Basin220192019
Lima220191999
St Mary120001991
Logan Pass120121988
Glen120021992
St Regis120141978
Arlee120241981
Highwood120241990
Brusett119851985

Common Merganser Population Trend in Other States

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

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