BirdAnalyst
Species · BCR 23 · BBS 2025 Release · 1966–2024

Common Merganser In Prairie Hardwood Transition

All regionsPrairie Hardwood TransitionWaterfowl

Common Merganser in Prairie Hardwood Transition has surged: up 76% on the route-weighted index since 1979.

+76%Since 1979TrendPercent 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 →
9Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
12YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 Common Merganser in Prairie Hardwood Transition. See the full index history below.

Routes In Prairie Hardwood Transition

Routes recording Common Merganser in Prairie Hardwood Transition.
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 →
GreshamWISCONSIN52024
DresserWISCONSIN21984
Brook ParkMINNESOTA12017
HudsonWISCONSIN12009
CochraneWISCONSIN11979
TrempealeauWISCONSIN11972
Wis RapidsWISCONSIN12019
ManawaWISCONSIN12008
ColbyWISCONSIN12000

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