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

Wilson's Warbler In BCR 4

All regionsBCR 4Forest birds

Wilson's Warbler in BCR 4 has edged up: up 20% on the route-weighted index since 1978.

+20%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 Wilson's Warbler in BCR 4. See the full index history below.

Wilson's Warbler In BCR 4 Population Forecast

If the recent trend holds, Wilson's Warbler in BCR 4 is projected to rise about 63% by 2030 — from 7.1 in 2025 to a central estimate of 12 (95% range 4.3–19). A 5-year backtest shows a typical error of ±70.3%, 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 →
12Projected 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 →
4.3–1995% 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 →
±70.3%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, Wilson's Warbler in BCR 4 is projected to rise about 63% by 2030 — from 7.1 in 2025 to a central estimate of 12 (95% range 4.3–19). A 5-year backtest shows a typical error of ±70.3%, 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 →
2026124.319
2027124.319
2028124.319
2029124.319
2030124.319

Routes In BCR 4

Routes recording Wilson's 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 →
ToklatALASKA732024
SavageALASKA432025
HomerALASKA421982
MaclarenALASKA412025
Paxson LakeALASKA371997
Caribou Mtn.ALASKA272025
Hatcher PassALASKA222025
MonahanALASKA192021
Mt. FairplayALASKA182025
Pinoche Tral (Short)ALASKA181984
DeltaALASKA172024
Lake LouiseALASKA152025
Kenny LakeALASKA142023
SourdoughALASKA132025
CircleALASKA112025
Chena RiverALASKA111988
ColdfootALASKA112025
CantwellALASKA102025
Goose BayALASKA101982
Kanuti LakeALASKA102024
NebesnaALASKA91975
ChistochinaALASKA92025
Donelly DomeALASKA92019
TatalinaALASKA82019
Nabesna RoadALASKA82025

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