BirdAnalyst
Species · BBS 2026 Release · 1966–2025

Hooded Merganser Population Analysis

AnatidaeWaterfowlLophodytes cucullatus

Hooded Merganser has surged: up 141% on the route-weighted index since 1968.

+141%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 →
441RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Hooded Merganser

The Hooded Merganser (Lophodytes cucullatus) is a North American member of the Ducks, Geese & Waterfowl (Anatidae). In this analysis it is grouped with the waterfowl.

Size
12–43.5 in long (30–110 cm) — a medium to large waterfowl (typical for the family)
Habitat
Lakes, ponds, rivers, marshes and sheltered coastal waters.
Diet
Aquatic plants, seeds and invertebrates, dabbled at the surface or dived for.
Range
Recorded on 441 Breeding Bird Survey routes across 37 states, most concentrated in the Boreal Hardwood Transition.
Family
Anatidae · Waterfowl

Notable Hooded Merganser TrendsNotable 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. See the full index history below.

Hooded Merganser Population Forecast

If the recent trend holds, Hooded Merganser is projected to stay roughly flat through 2030, near 0.03 (95% range 0.02–0.03). A 5-year backtest shows a typical error of ±17.7%, with 80% of held-out values landing inside the 95% band.

n/aChange by 2030TrendPercent 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 →
0.03Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.02–0.0395% 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 →
±17.7%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 is projected to stay roughly flat through 2030, near 0.03 (95% range 0.02–0.03). A 5-year backtest shows a typical error of ±17.7%, with 80% of held-out values landing inside the 95% band.19662030
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 →
20260.020.010.03
20270.020.010.03
20280.020.010.03
20290.030.020.03
20300.030.020.03

Where the Hooded Merganser Is Detected

BBS routes recording Hooded Merganser, sized by most recent count.

Hooded Merganser Population Trend by State

Hooded Merganser population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Alabamainsufficient datan/a2
Alaskainsufficient datan/a4
Arkansasinsufficient datan/a1
Coloradoinsufficient datan/a2
Connecticut-82%19835
Idahoinsufficient datan/a2
Illinois-60%199419
Indianainsufficient datan/a6
Iowainsufficient datan/a9
Kansasinsufficient datan/a2
Kentuckyinsufficient datan/a6
Maine+233%199127
Marylandinsufficient datan/a6
Massachusetts+62%200110
Michigan-5%199335
Minnesota-46%197855
Mississippiinsufficient datan/a4
Missouriinsufficient datan/a3
Montana+66%19969
Nebraskainsufficient datan/a7
New Hampshire+35%198219
New York-46%197036
North Dakota+811%199120
Ohioinsufficient datan/a6
Oklahomainsufficient datan/a2
Oregon-90%197511
Pennsylvania-33%199220
Rhode Islandinsufficient datan/a1
South Carolinainsufficient datan/a2
South Dakotainsufficient datan/a8
Tennesseeinsufficient datan/a2
Texasinsufficient datan/a2
Vermont+565%199212
Washington-64%198826
West Virginiainsufficient datan/a3
Wisconsin+9%196851
Wyominginsufficient datan/a6

Hooded Merganser Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Hooded Merganser population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Northern Pacific Rainforest-78%198428
Great Basin-49%19899
Northern Rockies-40%199116
Prairie Potholes+66%197350
Boreal Hardwood Transition+23%197068
Lower Great Lakes / St. Lawrence Plain-53%198520
Atlantic Northern Forest+598%196967
Eastern Tallgrass Prairie-56%199231
Prairie Hardwood Transition+78%196856
Central Hardwoods-52%19948
Appalachian Mountains-2%198238
New England / Mid-Atlantic Coast-44%198319

Hooded Merganser Conservation Status

Our route-weighted index shows it up about 141% since 1968.

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14. Trend is a route-weighted relative-abundance index, not an absolute population.