BirdAnalyst
Species · New Hampshire · BBS 2025 Release · 1966–2024

Common Merganser Population Trend in New Hampshire

All statesWaterfowl

Common Merganser in New Hampshire has surged: up 130% on the route-weighted index since 1976.

+130%Since 1976
12Routes In State
43Years

Notable Common Merganser Trends in New Hampshire

long arc increasecomputed index

Common Merganser has surged in New Hampshire: up 130% on the route-weighted index since 1976.

Common Merganser Population Forecast in New Hampshire

If the recent trend holds, Common Merganser in New Hampshire is projected to stay roughly flat through 2029, near 0.27 (95% range 0.07–0.47). A 5-year backtest shows a typical error of ±50.5%, with 80% of held-out values landing inside the 95% band.

-3%Change by 2029
0.27Projected 2029 index
0.07–0.4795% range
±50.5%Backtest error
19702029
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
20250.250.050.45
20260.250.050.45
20270.260.060.46
20280.260.060.46
20290.270.070.47

Common Merganser Survey Routes in New Hampshire

Routes recording Common Merganser in New Hampshire.
Walpole420241996
Marlow320212012
Glen320212005
Jefferson Hl220221988
Stratford220191978
Fitzwilliam120232007
Mt Chocorua120241978
Lempster120241994
Franconia120191970
Milan120191972
Dixvil Notch120141998
Clarksville120141976

Common Merganser Population Trend in Other States

alaskaarizonacaliforniacoloradoconnecticutidahomainemarylandmassachusettsmichiganminnesotamontananevadanew-jerseynew-mexiconew-yorknorth-dakotaohiooregonpennsylvaniasouth-dakotautahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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