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

Yellow Warbler In BCR 4

All regionsBCR 4Forest birds

Yellow Warbler in BCR 4 has declined: down 32% on the route-weighted index since 1978.

-32%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 →
46YearsYears 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.

Yellow Warbler In BCR 4 Population Forecast

If the recent trend holds, Yellow Warbler in BCR 4 is projected to rise about 63% by 2030 — from 4.0 in 2025 to a central estimate of 6.5 (95% range 1.8–11). A 5-year backtest shows a typical error of ±40.2%, with 100% of held-out values landing inside the 95% band.

+63%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 →
6.5Projected 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 →
1.8–1195% 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 →
±40.2%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 63% by 2030 — from 4.0 in 2025 to a central estimate of 6.5 (95% range 1.8–11). A 5-year backtest shows a typical error of ±40.2%, 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 →
20266.41.711
20276.41.711
20286.51.711
20296.51.811
20306.51.811

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
CircleALASKA242025
Bear CreekALASKA211991
Galena (Short)ALASKA202025
Kobuk River (Short)ALASKA181992
Koyukuk Riv.ALASKA152001
Hather CreekALASKA142024
Kanuti LakeALASKA112024
Tangle LakesALASKA101987
ToklatALASKA92024
Chena RiverALASKA91988
Chena Hot Spring 2ALASKA92025
Porcupine R.ALASKA92002
Birch LakeALASKA82025
MaclarenALASKA82025
McgrathALASKA82022
DeltaALASKA82024
Goose BayALASKA71982
Kenny LakeALASKA72025
Hatcher PassALASKA72025
Nicholai SlALASKA72025
RubyALASKA72025
L SalchaALASKA62025

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