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

Hermit Thrush Population Trend in Montana

All statesForest birds

Hermit Thrush in Montana has surged: up 738% on the route-weighted index since 1973.

+738%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 →
39Routes 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 →
54YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Hermit 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 →

Hermit Thrush has surged in Montana: up 738% on the route-weighted index since 1973.

Hermit Thrush Population Forecast in Montana

If the recent trend holds, Hermit Thrush in Montana is projected to rise about 102% by 2030 — from 0.65 in 2025 to a central estimate of 1.3 (95% range 0.81–1.8). A 5-year backtest shows a typical error of ±68.9%, with 20% of held-out values landing inside the 95% band.

+102%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 →
1.3Projected 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 →
0.81–1.895% 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 →
±68.9%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, Hermit Thrush in Montana is projected to rise about 102% by 2030 — from 0.65 in 2025 to a central estimate of 1.3 (95% range 0.81–1.8). A 5-year backtest shows a typical error of ±68.9%, with 20% of held-out values landing inside the 95% band.19702030
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 →
20261.20.721.7
20271.20.741.8
20281.30.761.8
20291.30.781.8
20301.30.811.8

Hermit Thrush Survey Routes in Montana

Routes recording Hermit 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 →
Threemile Wa1120251993
Cramer Creek1120192003
Elevation Mt1120251996
Pryor Mtn.720251995
Pagil Gulch720252015
Skalkaho719971992
Maynard Coulee620252017
Skalkho-Rye520221999
Whitefish Lake420242016
Red Rock420221977
Fish Creek420242022
Lima420251994
Sula320241977
Painted Rock320191992
Logan Pass220251988
Victor220251994
Greenough220031996
Arlee220181985
Woodman220211979
Greenoagh 2220112006
Thompson Riv220141993
Wise River220221993
Libby Dam119911984
Kalispell119831983
St Mary119801970

Hermit Thrush Population Trend in Other States

alaskaarizonacaliforniacoloradoconnecticutidahoindianamainemarylandmassachusettsmichiganminnesotanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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