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

Yellow Warbler In BCR 4

All regionsBCR 4Forest birds

Yellow Warbler in BCR 4 has edged down: down 23% on the route-weighted index since 1978.

-23%Since 1978TrendPercent 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 →
68Routes 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 →
45YearsYears 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 Yellow Warbler in BCR 4. See the full index history below.

Forecast

If the recent trend holds, Yellow Warbler in BCR 4 is projected to rise about 12% by 2029 — from 6.0 in 2024 to a central estimate of 6.8 (95% range 2.1–11). A 5-year backtest shows a typical error of ±24.3%, with 100% of held-out values landing inside the 95% band.

+12%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 →
6.8Projected 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 →
2.1–1195% 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 →
±24.3%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, Yellow Warbler in BCR 4 is projected to rise about 12% by 2029 — from 6.0 in 2024 to a central estimate of 6.8 (95% range 2.1–11). A 5-year backtest shows a typical error of ±24.3%, 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 →
20256.61.911
20266.72.011
20276.72.011
20286.72.011
20296.82.111

Routes In BCR 4

Routes recording Yellow Warbler 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 →
Anvik RiverALASKA422024
Unalakleet RiverALASKA262024
Mud RiverALASKA252024
Bear CreekALASKA211991
Kobuk River (Short)ALASKA181992
Koyukuk Riv.ALASKA152001
Galena (Short)ALASKA152024
Hather CreekALASKA142024
MaclarenALASKA122024
Kanuti LakeALASKA112024
Kenny LakeALASKA102024
Tangle LakesALASKA101987
CircleALASKA92024
ToklatALASKA92024
Chena RiverALASKA91988
Porcupine R.ALASKA92002
McgrathALASKA82022
DeltaALASKA82024
Goose BayALASKA71982
L SalchaALASKA62023
ChickenALASKA62024
Nicholai SlALASKA62024
WasillaALASKA51983
TonsinaALASKA42021
CohoeALASKA42023

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