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Species · Alaska · BBS 2025 Release · 1966–2024

Hermit Thrush Population Trend in Alaska

All statesForest birds

Hermit Thrush in Alaska has surged: up 155% on the route-weighted index since 1972.

+155%Since 1972TrendPercent 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 StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
51YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Hermit Thrush 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 →

Hermit Thrush has surged in Alaska: up 155% on the route-weighted index since 1972.

Hermit Thrush Population Forecast in Alaska

If the recent trend holds, Hermit Thrush in Alaska is projected to rise about 23% by 2029 — from 16 in 2024 to a central estimate of 20 (95% range 11–29). A 5-year backtest shows a typical error of ±39.8%, with 100% of held-out values landing inside the 95% band.

+23%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 →
20Projected 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 →
11–2995% 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 →
±39.8%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, Hermit Thrush in Alaska is projected to rise about 23% by 2029 — from 16 in 2024 to a central estimate of 20 (95% range 11–29). A 5-year backtest shows a typical error of ±39.8%, 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 →
2025191028
2026191128
2027201128
2028201129
2029201129

Hermit Thrush Survey Routes in Alaska

Routes recording Hermit Thrush 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 →
Yakutat (Short)11119841984
Yakutat8120241993
Kodiak 28120241985
Copper River7920111993
Harlequin L.7620241993
Chichagof Is7420241994
Chiniak7220241985
Thompson Pas6920241983
Cordova6320241983
Hoonah6320241993
Thorne Bay6020121989
Hope6020241985
Petersburg5919871987
Thorne Bay 25820242013
Seward5319921982
Mitkof Isle5020241988
Kodiak4819841983
Whale Pass4520241997
Sheep Mtn3720171983
Zarembo3620241993
Craig3520241983
Homer3319821977
Haines3320241972
Matanuska3319831982
Zimovia Strt3320241988

Hermit Thrush Population Trend in Other States

arizonacaliforniacoloradoconnecticutidahomainemarylandmassachusettsmichiganminnesotamontananevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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