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

Varied Thrush In BCR 4

All regionsBCR 4Forest birds

Varied Thrush in BCR 4 has held roughly steady: down 9% on the route-weighted index since 1976.

-9%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 Varied Thrush in BCR 4. See the full index history below.

Varied Thrush In BCR 4 Population Forecast

If the recent trend holds, Varied Thrush in BCR 4 is projected to stay roughly flat through 2030, near 9.5 (95% range 2.9–16). A 5-year backtest shows a typical error of ±41.9%, with 100% of held-out values landing inside the 95% band.

+6%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 →
9.5Projected 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 →
2.9–1695% 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 →
±41.9%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, Varied Thrush in BCR 4 is projected to stay roughly flat through 2030, near 9.5 (95% range 2.9–16). A 5-year backtest shows a typical error of ±41.9%, 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 →
202610.03.317
20279.83.216
20289.73.116
20299.63.016
20309.52.916

Routes In BCR 4

Routes recording Varied 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 →
TatalinaALASKA402019
HomerALASKA371982
WillowALASKA362025
PetersvilleALASKA302025
Unalakleet RiverALASKA272024
RubyALASKA262025
Bear CreekALASKA251991
ChistochinaALASKA242025
ChickenALASKA222025
WasillaALASKA201983
Mt. FairplayALASKA202025
MatanuskaALASKA191983
Goose BayALASKA181982
Kenny LakeALASKA152025
Kobuk River (Short)ALASKA151992
Skilak LakeALASKA141985
Seven LakesALASKA142025
Koyukuk Riv.ALASKA142001
Swan Lake RdALASKA132025
Anvik RiverALASKA132024
Mccarthy Rd2ALASKA132025
Birch LakeALASKA122025
Chena RiverALASKA121988
Murphy DomeALASKA122025
Nabesna RoadALASKA122025

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