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Species · Montana · BBS 2026 Release · 1966–2025

Swainson's Thrush Population Trend in Montana

All statesForest birds

Swainson's Thrush in Montana has surged: up 142% on the route-weighted index since 1970.

+142%Since 1970TrendPercent 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 →
46Routes 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 →
57YearsYears 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 MontanaNotable 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 →

Swainson's Thrush has surged in Montana: up 142% on the route-weighted index since 1970.

Swainson's Thrush Population Forecast in Montana

If the recent trend holds, Swainson's Thrush in Montana is projected to rise about 39% by 2030 — from 7.1 in 2025 to a central estimate of 9.8 (95% range 7.2–12). A 5-year backtest shows a typical error of ±13.6%, with 100% of held-out values landing inside the 95% band.

+39%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 →
9.8Projected 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 →
7.2–1295% 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 →
±13.6%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 Montana is projected to rise about 39% by 2030 — from 7.1 in 2025 to a central estimate of 9.8 (95% range 7.2–12). A 5-year backtest shows a typical error of ±13.6%, 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 →
20269.46.812
20279.56.912
20289.67.012
20299.77.112
20309.87.212

Swainson's Thrush Survey Routes in Montana

Routes recording Swainson's Thrush in Montana.
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 →
Libby Dam10720251979
Whitefish Lake9820242016
Swan Lake9020252015
Thompson Riv7620241993
Noxon6120231995
St Regis5720251977
Fish Creek5520241995
Skalkaho4519981992
Greenoagh 34420252012
Woodman3520251968
Arlee3120251969
Ninemile3120251993
Threemile Wa2820251993
Cramer Creek2520191994
East Glacier Park2420252015
Victor2220251993
Painted Rock2220221992
Inside Road2120251990
Logan Pass2020251980
Skalkho-Rye2020221999
Greenoagh 22020112005
Elevation Mt1720251996
Greenough1320041995
Clinton1120251975
Sula920241978

Swainson's Thrush Population Trend in Other States

alaskaarizonacaliforniacoloradoconnecticutidahoillinoismainemarylandmassachusettsmichiganminnesotanebraskanevadanew-hampshirenew-mexiconew-yorknorth-carolinaoregonpennsylvaniasouth-dakotautahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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