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Species · BCR 4 · BBS 2026 Release · 1966–2025

Swainson's Thrush In BCR 4

All regionsBCR 4Forest birds

Swainson's Thrush in BCR 4 has held roughly steady: up 8% on the route-weighted index since 1976.

+8%Since 1976TrendPercent 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 →
67Routes 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 →
48YearsYears 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 BCR 4. See the full index history below.

Swainson's Thrush In BCR 4 Population Forecast

If the recent trend holds, Swainson's Thrush in BCR 4 is projected to stay roughly flat through 2030, near 58 (95% range 37–80). A 5-year backtest shows a typical error of ±6.5%, with 100% of held-out values landing inside the 95% band.

+4%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 →
58Projected 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 →
37–8095% 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 →
±6.5%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 BCR 4 is projected to stay roughly flat through 2030, near 58 (95% range 37–80). A 5-year backtest shows a typical error of ±6.5%, 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 →
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Routes In BCR 4

Routes recording Swainson's Thrush in BCR 4.
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 →
Chena RiverALASKA1591988
DeltaALASKA1332024
Manley Ht SpALASKA1162022
Moose CreekALASKA1142022
Mccarthy Rd2ALASKA1142025
Kanuti LakeALASKA1132024
Ft. RichrdsnALASKA1022023
KuskulanaALASKA1022025
SourdoughALASKA1002025
Lake LouiseALASKA992025
Kanuti CanynALASKA982024
Tower BluffsALASKA952025
ChistochinaALASKA932025
Kenny LakeALASKA912025
Chena Hot Spring 2ALASKA902025
Swan Lake RdALASKA852025
Mud RiverALASKA852024
RubyALASKA842025
LivengoodALASKA822021
Burma RoadALASKA812025
CircleALASKA782025
NorthwayALASKA782025
Chatanika RALASKA752025
Nicholai SlALASKA752025
Hather CreekALASKA742024

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