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Species · Massachusetts · BBS 2026 Release · 1966–2025

Hooded Merganser Population Trend in Massachusetts

All statesWaterfowl

Hooded Merganser in Massachusetts has risen sharply: up 62% on the route-weighted index since 2001.

+62%Since 2001TrendPercent 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 →
10Routes 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 MassachusettsNotable 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 increasecomputed 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 risen sharply in Massachusetts: up 62% on the route-weighted index since 2001.

Hooded Merganser Survey Routes in Massachusetts

Routes recording Hooded Merganser in Massachusetts.
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 →
Monterey220192019
Ware River120172012
Maynard120252025
Littleton120132013
Belchertown120152015
Holden120072005
N Orange120221997
Chesterfield120212000
Warren 2120252019
Sheffield120002000

Hooded Merganser Population Trend in Other States

alabamaalaskaarkansascoloradoconnecticutidahoillinoisindianaiowakansaskentuckymainemarylandmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-yorknorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontwashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.