BirdAnalyst
Species · BCR 5 · BBS 2025 Release · 1966–2024

Common Merganser In Northern Pacific Rainforest

All regionsNorthern Pacific RainforestWaterfowl

Common Merganser in Northern Pacific Rainforest has declined: down 45% on the route-weighted index since 1970.

-45%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 →
56YearsYears 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 Northern Pacific Rainforest. See the full index history below.

Common Merganser In Northern Pacific Rainforest Population Forecast

If the recent trend holds, Common Merganser in Northern Pacific Rainforest is projected to rise about 288% by 2029 — from 0.29 in 2024 to a central estimate of 1.1 (95% range 0.00–2.5). A 5-year backtest shows a typical error of ±235%, with 100% of held-out values landing inside the 95% band.

+288%Change by 2029TrendPercent 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 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–2.595% 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 →
±235%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 288% by 2029 — from 0.29 in 2024 to a central estimate of 1.1 (95% range 0.00–2.5). A 5-year backtest shows a typical error of ±235%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20251.10.002.5
20261.10.002.5
20271.10.002.5
20281.10.002.5
20291.10.002.5

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
Warm BeachWASHINGTON82005
LongvaleCALIFORNIA72023
Bull RunOREGON72023
Junction CtyCALIFORNIA52012
TaholahWASHINGTON52022
Bodega BayCALIFORNIA42021
GlasgowOREGON42018
ProspectOREGON42009
MolallaOREGON42021
South ElmaWASHINGTON42017
KetchikanALASKA32001
HyderALASKA32007
Sitka (Short)ALASKA31992
Shasta LakeCALIFORNIA32007
WedderburnOREGON32004
Emigrant Lake 2OREGON32019
Hurricane RgWASHINGTON32023
JuneauALASKA21989
Thorne BayALASKA22001

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