BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

Varied Thrush In Great Basin

All regionsGreat BasinForest birds

Varied Thrush in Great Basin has declined: down 47% on the route-weighted index since 1970.

-47%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 →
30Routes 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 →
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 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 Great Basin. See the full index history below.

Varied Thrush In Great Basin Population Forecast

If the recent trend holds, Varied Thrush in Great Basin is projected to rise about 43% by 2029 — from 0.38 in 2024 to a central estimate of 0.54 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±72.2%, with 100% of held-out values landing inside the 95% band.

+43%Change by 2029TrendPercent 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 →
0.54Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–1.595% 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 →
±72.2%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 Great Basin is projected to rise about 43% by 2029 — from 0.38 in 2024 to a central estimate of 0.54 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±72.2%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.590.001.6
20260.580.001.5
20270.560.001.5
20280.550.001.5
20290.540.001.5

Routes In Great Basin

Routes recording Varied Thrush in Great Basin.
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 →
Cascade RivWASHINGTON212006
GlacierWASHINGTON172024
White ChuckWASHINGTON162024
IndexWASHINGTON131997
NewhalemWASHINGTON82024
IndexWASHINGTON81971
SnowdenWASHINGTON81973
Suiattle RivWASHINGTON72019
JosephOREGON51984
Index 2WASHINGTON52023
No CascadesWASHINGTON52019
RimrockWASHINGTON42024
KendallWASHINGTON42024
WinthropWASHINGTON31999
Camp ShermanOREGON21986
Davis LakeOREGON22001
SistersOREGON22012
TwispWASHINGTON22008
RonaldWASHINGTON22024
CarltonWASHINGTON21999
MazamaWASHINGTON22022
L. WenatcheeWASHINGTON22023
ConcreteWASHINGTON22024
E. Mt. AdamsWASHINGTON22011
Barnes ValOREGON11971

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.