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Species · BCR 4 · BBS 2025 Release · 1966–2024

Swainson's Thrush In BCR 4

All regionsBCR 4Forest birds

Swainson's Thrush in BCR 4 has edged up: up 14% on the route-weighted index since 1976.

+14%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 →
47YearsYears 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.

Forecast

If the recent trend holds, Swainson's Thrush in BCR 4 is projected to stay roughly flat through 2029, near 58 (95% range 36–80). A 5-year backtest shows a typical error of ±12.9%, with 100% of held-out values landing inside the 95% band.

-1%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 →
58Projected 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 →
36–8095% 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 →
±12.9%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 2029, near 58 (95% range 36–80). A 5-year backtest shows a typical error of ±12.9%, 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 →
2025563478
2026573579
2027573579
2028583680
2029583680

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
Kenny LakeALASKA1182024
Manley Ht SpALASKA1162022
Moose CreekALASKA1142022
Kanuti LakeALASKA1132024
Mccarthy Rd2ALASKA1132024
ChistochinaALASKA1082024
Chena Hot Spring 2ALASKA1072024
Ft. RichrdsnALASKA1022023
SourdoughALASKA992024
Burma RoadALASKA992024
Kanuti CanynALASKA982024
KuskulanaALASKA972024
Mud RiverALASKA852024
LivengoodALASKA822021
Nicholai SlALASKA802024
RubyALASKA762024
Tower BluffsALASKA742023
Hather CreekALASKA742024
TatalinaALASKA732019
CircleALASKA662024
McgrathALASKA642022
TonsinaALASKA632021
WasillaALASKA631983

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