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Species · Alaska · BBS 2026 Release · 1966–2025

Varied Thrush Population Trend in Alaska

All statesForest birds

Varied Thrush in Alaska has surged: up 135% on the route-weighted index since 1973.

+135%Since 1973TrendPercent 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 →
119Routes 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 Varied 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 →

Varied Thrush has surged in Alaska: up 135% on the route-weighted index since 1973.

Varied Thrush Population Forecast in Alaska

If the recent trend holds, Varied Thrush in Alaska is projected to rise about 48% by 2030 — from 16 in 2025 to a central estimate of 24 (95% range 14–33). A 5-year backtest shows a typical error of ±38%, with 100% of held-out values landing inside the 95% band.

+48%Change by 2030TrendPercent 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 →
24Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
14–3395% 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 →
±38%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, Varied Thrush in Alaska is projected to rise about 48% by 2030 — from 16 in 2025 to a central estimate of 24 (95% range 14–33). A 5-year backtest shows a typical error of ±38%, with 100% of held-out values landing inside the 95% band.19682030
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 →
2026231433
2027231433
2028231433
2029241433
2030241433

Varied Thrush Survey Routes in Alaska

Routes recording Varied 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 →
Chichagof Is15520241994
Hoonah14520241993
Copper River9820111993
Seward9519921982
Yakutat (Short)9419841984
Kuiu Island9320102004
Petersburg7919871987
Craig6920251983
Stikine River6920241998
Thorne Bay 26220252013
Harlequin L.5920241993
Hyder5920091994
Haines5520251972
Mitkof Isle5320251988
Tupuknuk5219951995
Chiniak5020251985
Sitka (Short)5019921984
Yakutat4720251993
Hope4620251985
Whale Pass4620241997
Dillingham4520191993
Tatalina4020191995
Moose Pass3919921983
Homer3719821977
Juneau3720251983

Varied Thrush Population Trend in Other States

californiaidahomontanaoregonwashington

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.