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

Wilson's Warbler In BCR 4

All regionsBCR 4Forest birds

Wilson's Warbler in BCR 4 has edged up: up 22% on the route-weighted index since 1978.

+22%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 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 32% by 2029 — from 9.2 in 2024 to a central estimate of 12 (95% range 4.9–19). A 5-year backtest shows a typical error of ±50.3%, with 100% of held-out values landing inside the 95% band.

+32%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 →
12Projected 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 →
4.9–1995% 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 →
±50.3%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 32% by 2029 — from 9.2 in 2024 to a central estimate of 12 (95% range 4.9–19). A 5-year backtest shows a typical error of ±50.3%, 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 →
2025124.819
2026124.819
2027124.819
2028124.919
2029124.919

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
SavageALASKA542024
MaclarenALASKA422024
HomerALASKA421982
Paxson LakeALASKA371997
CircleALASKA262024
Caribou Mtn.ALASKA212024
MonahanALASKA192021
Pinoche Tral (Short)ALASKA181984
DeltaALASKA172024
Kenny LakeALASKA142023
Chena RiverALASKA111988
Hatcher PassALASKA112024
CantwellALASKA102021
Goose BayALASKA101982
Kanuti LakeALASKA102024
Nabesna RoadALASKA102024
Chatanika RALASKA92023
NebesnaALASKA91975
Donelly DomeALASKA92019
TatalinaALASKA82019
Lake LouiseALASKA72014
Unalakleet RiverALASKA72024
Mt. FairplayALASKA72024
Anvik RiverALASKA72024

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