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

Common Merganser Population Trend in Washington

All statesWaterfowl

Common Merganser in Washington has held roughly steady: down 3% on the route-weighted index since 1971.

-3%Since 1971
53Routes In State
55Years

Notable Common Merganser Trends in Washington

No notable trend signals for Common Merganser in Washington. See the full index history below.

Common Merganser Population Forecast in Washington

If the recent trend holds, Common Merganser in Washington is projected to rise about 23% by 2029 — from 0.39 in 2024 to a central estimate of 0.48 (95% range 0.03–0.92). A 5-year backtest shows a typical error of ±19.6%, with 100% of held-out values landing inside the 95% band.

+23%Change by 2029
0.48Projected 2029 index
0.03–0.9295% range
±19.6%Backtest error
19692029
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
20250.460.010.91
20260.460.010.91
20270.470.020.92
20280.470.020.92
20290.480.030.92

Common Merganser Survey Routes in Washington

Routes recording Common Merganser in Washington.
Deception8420172017
Warm Beach820051970
Rimrock820231980
No Cascades619961996
Nighthawk620241996
Newhalem520241969
Taholah520221978
Sullivan Lk519991999
Brewster420152015
Leavenworth419901984
South Elma420171986
Sullivan Lake 2320232000
Spring Lake320212018
Hurricane Rg320231992
Yakima320241993
Twisp220241969
Bunker Hill219981985
Ronald220241973
Ilwaco219961995
White Chuck220231992
Horn Rapids220192008
Mt St Helens220021994
Laurier220181999
Rainier220041996
Ozette120241974

Common Merganser Population Trend in Other States

alaskaarizonacaliforniacoloradoconnecticutidahomainemarylandmassachusettsmichiganminnesotamontananevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-dakotaohiooregonpennsylvaniasouth-dakotautahvermontvirginiawest-virginiawisconsinwyoming

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