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

Swainson's Thrush In Great Basin

All regionsGreat BasinForest birds

Swainson's Thrush in Great Basin 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 →
66Routes 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 Swainson's Thrush in Great Basin. See the full index history below.

Forecast

If the recent trend holds, Swainson's Thrush in Great Basin is projected to rise about 17% by 2029 — from 2.6 in 2024 to a central estimate of 3.1 (95% range 1.7–4.5). A 5-year backtest shows a typical error of ±11.5%, with 100% of held-out values landing inside the 95% band.

+17%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 →
3.1Projected 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 →
1.7–4.595% 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 →
±11.5%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, Swainson's Thrush in Great Basin is projected to rise about 17% by 2029 — from 2.6 in 2024 to a central estimate of 3.1 (95% range 1.7–4.5). A 5-year backtest shows a typical error of ±11.5%, 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 →
20253.11.64.5
20263.11.74.5
20273.11.74.5
20283.11.74.5
20293.11.74.5

Routes In Great Basin

Routes recording Swainson's 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 →
KendallWASHINGTON642024
ConcreteWASHINGTON642024
IndexWASHINGTON491971
Index 2WASHINGTON412023
NewhalemWASHINGTON402024
Suiattle RivWASHINGTON382019
White ChuckWASHINGTON372024
GlacierWASHINGTON352024
IndexWASHINGTON351997
Blewett PassWASHINGTON322024
CarltonWASHINGTON292022
L. WenatcheeWASHINGTON262024
Cascade RivWASHINGTON252006
HyrumUTAH171979
WinthropWASHINGTON162022
LeavenworthWASHINGTON162024
JarbidgeNEVADA142015
No CascadesWASHINGTON142019
RimrockWASHINGTON122024
Silver CityIDAHO102014
Mt HoodOREGON92024
SnowdenWASHINGTON92024
MazamaWASHINGTON92022
RonaldWASHINGTON82024
Dinner StaNEVADA71968

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