BirdAnalyst
Species · Montana · BBS 2026 Release · 1966–2025

Varied Thrush Population Trend in Montana

All statesForest birds

Varied Thrush in Montana has edged down: down 21% on the route-weighted index since 1971.

-21%Since 1971TrendPercent 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 →
24Routes 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 →
56YearsYears 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 MontanaNotable 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 Varied Thrush in Montana. See the full index history below.

Varied Thrush Population Forecast in Montana

If the recent trend holds, Varied Thrush in Montana is projected to rise about 367% by 2030 — from 0.13 in 2025 to a central estimate of 0.62 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±144.1%, with 100% of held-out values landing inside the 95% band.

+367%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 →
0.62Projected 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 →
0.00–1.795% 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 →
±144.1%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 Montana is projected to rise about 367% by 2030 — from 0.13 in 2025 to a central estimate of 0.62 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±144.1%, 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 →
20260.640.001.7
20270.630.001.7
20280.630.001.7
20290.630.001.7
20300.620.001.7

Varied Thrush Survey Routes in Montana

Routes recording Varied 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 →
Skalkaho1919981992
Whitefish Lake1120242016
Inside Road520251990
Logan Pass320251980
Skalkho-Rye320151999
St Mary219701970
Victor220111999
Greenough220021998
Arlee220251968
Sula220001991
Swan Lake220242017
Noxon220231995
Libby Dam119881979
Kalispell119901984
Threemile Wa120241994
St Regis120251977
Polson119891989
Woodman120231970
Clinton120241975
East Glacier Park120242016
Thompson Riv120231993
Ninemile120181994
Fish Creek120211995
Painted Rock120161994

Varied Thrush Population Trend in Other States

alaskacaliforniaidahooregonwashington

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