BirdAnalyst
Species · BCR 10 · BBS 2026 Release · 1966–2025

Varied Thrush In Northern Rockies

All regionsNorthern RockiesForest birds

Varied Thrush in Northern Rockies has declined: down 30% on the route-weighted index since 1970.

-30%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 →
69Routes In RegionSurvey 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 SignalsNotable 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 Northern Rockies. See the full index history below.

Varied Thrush In Northern Rockies Population Forecast

If the recent trend holds, Varied Thrush in Northern Rockies is projected to rise about 174% by 2030 — from 0.43 in 2025 to a central estimate of 1.2 (95% range 0.00–2.5). A 5-year backtest shows a typical error of ±145.4%, with 100% of held-out values landing inside the 95% band.

+174%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 →
1.2Projected 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 →
0.00–2.595% 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 →
±145.4%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 Northern Rockies is projected to rise about 174% by 2030 — from 0.43 in 2025 to a central estimate of 1.2 (95% range 0.00–2.5). A 5-year backtest shows a typical error of ±145.4%, 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 →
20261.20.002.5
20271.20.002.5
20281.20.002.5
20291.20.002.5
20301.20.002.5

Routes In Northern Rockies

Routes recording Varied Thrush in Northern Rockies.
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 →
Lolo PassIDAHO322019
GrangevilleIDAHO192025
SkalkahoMONTANA191998
Baldy MountainIDAHO162016
AveryIDAHO152025
Whitefish LakeMONTANA112024
Sullivan Lake 2WASHINGTON112025
PierceIDAHO102007
Marble CreekIDAHO92025
NorthportWASHINGTON92007
N Fork Cda RIDAHO62019
Inside RoadMONTANA52025
CascadeIDAHO41983
AlturasIDAHO41968
Rochat DivdeIDAHO42024
Sullivan LkWASHINGTON41999
CoolinIDAHO32024
Skalkho-RyeMONTANA32015
Logan PassMONTANA32025
L Pend O NwrWASHINGTON32022
NaplesIDAHO22022
NezperceIDAHO22012
GoldenIDAHO22016
Nezperce NfIDAHO21999
St MaryMONTANA21970

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