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Species · BCR 5 · BBS 2026 Release · 1966–2025

Common Merganser In Northern Pacific Rainforest

All regionsNorthern Pacific RainforestWaterfowl

Common Merganser in Northern Pacific Rainforest has fallen sharply: down 53% on the route-weighted index since 1970.

-53%Since 1970TrendPercent 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 →
107Routes 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 →
57YearsYears 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 →

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 →

Common Merganser has fallen sharply in Northern Pacific Rainforest: down 53% on the route-weighted index since 1970.

Common Merganser In Northern Pacific Rainforest Population Forecast

If the recent trend holds, Common Merganser in Northern Pacific Rainforest is projected to rise about 340% by 2030 — from 0.24 in 2025 to a central estimate of 1.1 (95% range 0.00–2.4). A 5-year backtest shows a typical error of ±284.4%, with 100% of held-out values landing inside the 95% band.

+340%Change 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 →
1.1Projected 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 →
0.00–2.495% 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 →
±284.4%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, Common Merganser in Northern Pacific Rainforest is projected to rise about 340% by 2030 — from 0.24 in 2025 to a central estimate of 1.1 (95% range 0.00–2.4). A 5-year backtest shows a typical error of ±284.4%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20261.10.002.4
20271.10.002.4
20281.10.002.4
20291.10.002.4
20301.10.002.4

Routes In Northern Pacific Rainforest

Routes recording Common Merganser in Northern Pacific Rainforest.
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 →
Cool CampOREGON3132013
DeceptionWASHINGTON842017
AlderpointCALIFORNIA182006
Horse CreekCALIFORNIA152019
Copper RiverALASKA122011
SaladoOREGON112024
Zimovia StrtALASKA82025
Warm BeachWASHINGTON82005
LongvaleCALIFORNIA72023
Bull RunOREGON72023
Junction CtyCALIFORNIA52012
TaholahWASHINGTON52022
Bodega BayCALIFORNIA42021
GlasgowOREGON42018
ProspectOREGON42009
MolallaOREGON42021
South ElmaWASHINGTON42017
KetchikanALASKA32001
HyderALASKA32007
Sitka (Short)ALASKA31992
WedderburnOREGON32004
Emigrant Lake 2OREGON32019
OzetteWASHINGTON32025
JuneauALASKA21989
Thorne BayALASKA22001

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