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Species · Alaska · BBS 2025 Release · 1966–2024

Swainson's Thrush Population Trend in Alaska

All statesForest birds

Swainson's Thrush in Alaska has held roughly steady: down 6% on the route-weighted index since 1972.

-6%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 →
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 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 2029, near 39 (95% range 18–59). A 5-year backtest shows a typical error of ±15.8%, with 100% of held-out values landing inside the 95% band.

-2%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 →
39Projected 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 →
18–5995% 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 →
±15.8%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, Swainson's Thrush in Alaska is projected to stay roughly flat through 2029, near 39 (95% range 18–59). A 5-year backtest shows a typical error of ±15.8%, 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 →
2025381858
2026381858
2027381858
2028381859
2029391859

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
Kenny Lake11820241983
Manley Ht Sp11620221993
Moose Creek11420221993
Mccarthy Rd211320241989
Kanuti Lake11320242006
Chistochina10820241990
Chena Hot Spring 210720241999
Ft. Richrdsn10220231994
Sourdough9920241983
Burma Road9920241996
Kanuti Canyn9820241993
Kuskulana9720241990
Mud River8520241993
Livengood8220212006
Nicholai Sl8020241993
Craig7720241983
Ruby7620241994
Tower Bluffs7420231994
Hather Creek7420241993
Tatalina7320191995
Circle6620241986
Hoonah6420241993
Mcgrath6420221997

Swainson's Thrush Population Trend in Other States

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

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