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

Hooded Merganser In Northern Pacific Rainforest

All regionsNorthern Pacific RainforestWaterfowl

Hooded Merganser in Northern Pacific Rainforest has fallen sharply: down 74% on the route-weighted index since 1984.

-74%Since 1984TrendPercent 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 →
28Routes 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 →
30YearsYears 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 →

Hooded Merganser has fallen sharply in Northern Pacific Rainforest: down 74% on the route-weighted index since 1984.

Hooded Merganser In Northern Pacific Rainforest Population Forecast

If the recent trend holds, Hooded Merganser in Northern Pacific Rainforest is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.06). A 5-year backtest shows a typical error of ±176.5%, with 80% of held-out values landing inside the 95% band.

n/aChange 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 →
0.00Projected 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 →
0.00–0.0695% 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 →
±176.5%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, Hooded Merganser in Northern Pacific Rainforest is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.06). A 5-year backtest shows a typical error of ±176.5%, with 80% of held-out values landing inside the 95% band.19752029
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 →
20250.000.000.06
20260.000.000.06
20270.000.000.06
20280.000.000.06
20290.000.000.06

Routes In Northern Pacific Rainforest

Routes recording Hooded 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 →
MendotaWASHINGTON51988
AdairOREGON32004
Pe EllWASHINGTON31997
Stikine RiverALASKA22002
WedderburnOREGON21990
GlasgowOREGON22005
SalemOREGON22013
Riley PeakOREGON22010
IlwacoWASHINGTON22022
MontesandWASHINGTON21993
HainesALASKA11997
Whale PassALASKA12002
ZaremboALASKA12004
SaladoOREGON12011
UmpquaOREGON12023
Nicolai Mtn.OREGON12006
Trask SummitOREGON12019
OzetteWASHINGTON12009
Port AngelesWASHINGTON12023
Warm BeachWASHINGTON12010
CamasWASHINGTON11995
South ElmaWASHINGTON12024
PackwoodWASHINGTON12013
Hurricane RgWASHINGTON12023
RainierWASHINGTON12019

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