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

Hooded Merganser Population Trend in Oregon

All statesWaterfowl

Hooded Merganser in Oregon has collapsed: down 86% on the route-weighted index since 1975.

-86%Since 1975TrendPercent 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 →
11Routes 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 →
15YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Hooded Merganser Trends in OregonNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Hooded Merganser has collapsed in Oregon: down 86% on the route-weighted index since 1975.

Hooded Merganser Survey Routes in Oregon

Routes recording Hooded Merganser in Oregon.
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 →
Joseph620052005
Adair320041975
Riley Peak220102010
Salem220132013
Glasgow220052005
Wedderburn219901975
Salado120112011
Trask Summit120192019
Nicolai Mtn.120061999
Umpqua120232023
Dell Spring119721968

Hooded Merganser Population Trend in Other States

alabamaalaskaarkansascoloradoconnecticutidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-yorknorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontwashingtonwest-virginiawisconsinwyoming

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