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Species · BCR 3 · BBS 2026 Release · 1966–2025

Arctic Warbler In BCR 3

All regionsBCR 3Forest birds

Arctic Warbler in BCR 3 has surged: up 211% on the route-weighted index since 1998.

+211%Since 1998TrendPercent 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 →
4Routes 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 →
18YearsYears 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 →

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Arctic Warbler has surged in BCR 3: up 211% on the route-weighted index since 1998.

Arctic Warbler In BCR 3 Population Forecast

If the recent trend holds, Arctic Warbler in BCR 3 is projected to fall about 63% by 2030 — from 3.5 in 2025 to a central estimate of 1.3 (95% range 0.00–3.0). A 5-year backtest shows a typical error of ±165.2%, with 80% 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 →
1.3Projected 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 →
0.00–3.095% 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 →
±165.2%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, Arctic Warbler in BCR 3 is projected to fall about 63% by 2030 — from 3.5 in 2025 to a central estimate of 1.3 (95% range 0.00–3.0). A 5-year backtest shows a typical error of ±165.2%, with 80% of held-out values landing inside the 95% band.19932030
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 →
20261.20.003.0
20271.20.003.0
20281.30.003.0
20291.30.003.0
20301.30.003.0

Routes In BCR 3

Routes recording Arctic Warbler in BCR 3.
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 →
Red DogALASKA122025
Dietrich CmpALASKA62014
Galbraith L.ALASKA12025
Happy ValleyALASKA12025

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