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Species · Alaska · BBS 2025 Release · 1966–2024

Marbled Murrelet Population Trend in Alaska

All statesGeneralists

Marbled Murrelet in Alaska has surged: up 97% on the route-weighted index since 1977.

+97%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 →
26Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
44YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Marbled Murrelet Trends in AlaskaNotable 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 Alaska: up 97% on the route-weighted index since 1977.

Marbled Murrelet Population Forecast in Alaska

If the recent trend holds, Marbled Murrelet in Alaska is projected to fall about 77% by 2029 — from 2.8 in 2024 to a central estimate of 0.65 (95% range 0.00–6.4). A 5-year backtest shows a typical error of ±20.5%, with 100% of held-out values landing inside the 95% band.

-77%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 →
0.65Projected 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 →
0.00–6.495% 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 →
±20.5%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, Marbled Murrelet in Alaska is projected to fall about 77% by 2029 — from 2.8 in 2024 to a central estimate of 0.65 (95% range 0.00–6.4). A 5-year backtest shows a typical error of ±20.5%, 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 →
20250.850.006.6
20260.800.006.6
20270.750.006.5
20280.700.006.5
20290.650.006.4

Marbled Murrelet Survey Routes in Alaska

Routes recording Marbled Murrelet in Alaska.
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 →
Sitka14120241997
Adak11919971984
Petersburg10619871984
Juneau Alt3019861984
Whale Pass2420141997
Chiniak1720241986
Chichagof Is1420241995
Thorne Bay920121992
Skagway820131997
Hoonah520231993
Cordova520222004
Ketchikan420221972
Zimovia Strt420241990
Haines320241975
Yakutat320231993
Kuiu Island220102004
Zarembo220211993
Harlequin L.220241994
Kodiak 2220191994
Stikine River120242002
Juneau120241983
Craig120241994
Beaver Creek119771977
Copper River120112011
Mitkof Isle120231988

Marbled Murrelet Population Trend in Other States

californiaoregonwashington

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