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Species · Alaska · BBS 2026 Release · 1966–2025

Swainson's Thrush Population Trend in Alaska

All statesForest birds

Swainson's Thrush in Alaska has held roughly steady: down 8% on the route-weighted index since 1972.

-8%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 →
109Routes 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 →
52YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Swainson's 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 →

No notable trend signals for Swainson's Thrush in Alaska. See the full index history below.

Swainson's Thrush Population Forecast in Alaska

If the recent trend holds, Swainson's Thrush in Alaska is projected to stay roughly flat through 2030, near 39 (95% range 19–59). A 5-year backtest shows a typical error of ±11.2%, with 100% of held-out values landing inside the 95% band.

-6%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 →
39Projected 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 →
19–5995% 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 →
±11.2%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, Swainson's Thrush in Alaska is projected to stay roughly flat through 2030, near 39 (95% range 19–59). A 5-year backtest shows a typical error of ±11.2%, 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 →
2026381858
2027391859
2028391959
2029391959
2030391959

Swainson's Thrush Survey Routes in Alaska

Routes recording Swainson's 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 →
Chena River15919881988
Delta13320241995
Manley Ht Sp11620221993
Mccarthy Rd211420251989
Moose Creek11420221993
Kanuti Lake11320242006
Kuskulana10220251990
Ft. Richrdsn10220231994
Sourdough10020251983
Lake Louise9920251993
Kanuti Canyn9820241993
Tower Bluffs9520251994
Chistochina9320251990
Kenny Lake9120251983
Chena Hot Spring 29020251999
Craig8520251983
Swan Lake Rd8520251982
Mud River8520241993
Ruby8420251994
Livengood8220212006
Burma Road8120251996
Circle7820251986
Northway7820251989
Chatanika R7520251968
Nicholai Sl7520251993

Swainson's Thrush Population Trend in Other States

arizonacaliforniacoloradoconnecticutidahoillinoismainemarylandmassachusettsmichiganminnesotamontananebraskanevadanew-hampshirenew-mexiconew-yorknorth-carolinaoregonpennsylvaniasouth-dakotautahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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