BirdAnalyst
Species · BCR 16 · BBS 2025 Release · 1966–2024

Swainson's Thrush In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauForest birds

Swainson's Thrush in Southern Rockies / Colorado Plateau has surged: up 109% on the route-weighted index since 1972.

+109%Since 1972TrendPercent 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 →
79Routes 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 →
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 SignalsNotable 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 →

Swainson's Thrush has surged in Southern Rockies / Colorado Plateau: up 109% on the route-weighted index since 1972.

Swainson's Thrush In Southern Rockies / Colorado Plateau Population Forecast

If the recent trend holds, Swainson's Thrush in Southern Rockies / Colorado Plateau is projected to rise about 26% by 2029 — from 0.40 in 2024 to a central estimate of 0.50 (95% range 0.13–0.86). A 5-year backtest shows a typical error of ±54.1%, with 100% of held-out values landing inside the 95% band.

+26%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 →
0.50Projected 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 →
0.13–0.8695% 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 →
±54.1%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 Southern Rockies / Colorado Plateau is projected to rise about 26% by 2029 — from 0.40 in 2024 to a central estimate of 0.50 (95% range 0.13–0.86). A 5-year backtest shows a typical error of ±54.1%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20250.480.120.84
20260.480.120.85
20270.490.130.85
20280.490.130.86
20290.500.130.86

Routes In Southern Rockies / Colorado Plateau

Routes recording Swainson's Thrush in Southern Rockies / Colorado Plateau.
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 →
AspenCOLORADO92024
Main CanyonUTAH92003
Moon Lake 2UTAH92023
YampaCOLORADO62023
SoapstoneUTAH62024
Moon LakeUTAH62002
YampaiARIZONA51969
ParlinCOLORADO52022
Dunckley PasCOLORADO52024
Rifle FallsCOLORADO52021
Stillwater Pass 2COLORADO52024
HarmonyCOLORADO41975
WarbonnetWYOMING42024
Deadman Rd.COLORADO32024
Steamboat L.COLORADO32024
Comanche PkCOLORADO32024
ComoCOLORADO32021
BeckUTAH31970
BeaverUTAH31973
Uintah NfUTAH31994
Fish Lake NfUTAH31996
GooseberryUTAH32024
Ryan ParkWYOMING32023
Lost LakeCOLORADO22022
DoylevilleCOLORADO22021

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