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Species · Colorado · BBS 2026 Release · 1966–2025

Hermit Thrush Population Trend in Colorado

All statesForest birds

Hermit Thrush in Colorado has surged: up 247% on the route-weighted index since 1970.

+247%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 →
82Routes 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 Hermit Thrush Trends in ColoradoNotable 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 Colorado: up 247% on the route-weighted index since 1970.

Hermit Thrush Population Forecast in Colorado

If the recent trend holds, Hermit Thrush in Colorado is projected to rise about 80% by 2030 — from 3.5 in 2025 to a central estimate of 6.4 (95% range 4.4–8.4). A 5-year backtest shows a typical error of ±54.8%, with 0% of held-out values landing inside the 95% band.

+80%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 →
6.4Projected 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 →
4.4–8.495% 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 →
±54.8%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, Hermit Thrush in Colorado is projected to rise about 80% by 2030 — from 3.5 in 2025 to a central estimate of 6.4 (95% range 4.4–8.4). A 5-year backtest shows a typical error of ±54.8%, with 0% 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 →
20266.04.08.0
20276.14.18.1
20286.24.28.2
20296.34.38.3
20306.44.48.4

Hermit Thrush Survey Routes in Colorado

Routes recording Hermit Thrush in Colorado.
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 →
Pinos Creek4419901988
Mcphee Res.3720251996
Mount Evans3420241996
Guanella Pas2820251992
Baxter Pass2520241994
Pinon2420251992
Lake City2220031988
Heeney 22020252025
Haycamp Mesa1920251998
Buffalo Park1820251992
Cochetopa Pass1620251998
Flattops1520251992
Dunckley Pas1420251992
Weston Pass1420001994
Stillwater Pass1420092005
Nucla1320251999
Red Cliff1220251989
South Fork1220251994
Owl Creek Pass1220251998
Moon Pass1220241998
Como1120251994
Rollins Pass1120251998
Lizard Head Pass1120252001
Radium1020121998
Willow Peak920251988

Hermit Thrush Population Trend in Other States

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

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