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

Marbled Murrelet In Northern Pacific Rainforest

All regionsNorthern Pacific RainforestGeneralists

Marbled Murrelet in Northern Pacific Rainforest has surged: up 26× on the route-weighted index since 1977.

26×Since 1977TrendPercent 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 →
36Routes 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 →
46YearsYears 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 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 →

Marbled Murrelet has surged in Northern Pacific Rainforest: up 26× on the route-weighted index since 1977.

Marbled Murrelet In Northern Pacific Rainforest Population Forecast

If the recent trend holds, Marbled Murrelet in Northern Pacific Rainforest is projected to fall about 55% by 2029 — from 2.2 in 2024 to a central estimate of 1.0 (95% range 0.00–3.3). A 5-year backtest shows a typical error of ±74.9%, with 100% of held-out values landing inside the 95% band.

-55%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 →
1.0Projected 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 →
0.00–3.395% 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 →
±74.9%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, Marbled Murrelet in Northern Pacific Rainforest is projected to fall about 55% by 2029 — from 2.2 in 2024 to a central estimate of 1.0 (95% range 0.00–3.3). A 5-year backtest shows a typical error of ±74.9%, with 100% of held-out values landing inside the 95% band.19722029
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 →
20250.990.003.3
20261.000.003.3
20271.000.003.3
20281.00.003.3
20291.00.003.3

Routes In Northern Pacific Rainforest

Routes recording Marbled Murrelet 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 →
SitkaALASKA1412024
PetersburgALASKA1061987
Juneau AltALASKA301986
Warm BeachWASHINGTON272002
Whale PassALASKA242014
Redwood N.P. 2CALIFORNIA192013
Chichagof IsALASKA142024
Thorne BayALASKA92012
SkagwayALASKA82013
CordovaALASKA52022
HoonahALASKA52023
KetchikanALASKA42022
Zimovia StrtALASKA42024
HainesALASKA32024
YakutatALASKA32023
Harlequin L.ALASKA22024
ZaremboALASKA22021
Kuiu IslandALASKA22010
HoneydewCALIFORNIA21982
HolmesCALIFORNIA22022
WaldportOREGON21994
Myrtle GroveOREGON22001
Klickitat MtOREGON21994
Riley PeakOREGON22016
JuneauALASKA12024

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