BirdAnalyst
Species · BCR 2 · BBS 2025 Release · 1966–2024

Arctic Warbler In BCR 2

All regionsBCR 2Generalists

Arctic Warbler in BCR 2 has declined: down 36% on the route-weighted index since 1994.

-36%Since 1994TrendPercent 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 →
14Routes 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 →
31YearsYears 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 Arctic Warbler in BCR 2. See the full index history below.

Arctic Warbler In BCR 2 Population Forecast

If the recent trend holds, Arctic Warbler in BCR 2 is projected to stay roughly flat through 2029, near 7.0 (95% range 0.00–16). A 5-year backtest shows a typical error of ±255%, with 60% of held-out values landing inside the 95% band.

-10%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 →
7.0Projected 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 →
0.00–1695% 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 →
±255%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 2 is projected to stay roughly flat through 2029, near 7.0 (95% range 0.00–16). A 5-year backtest shows a typical error of ±255%, with 60% of held-out values landing inside the 95% band.19842029
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 →
20257.80.0017
20267.60.0016
20277.40.0016
20287.20.0016
20297.00.0016

Routes In BCR 2

Routes recording Arctic Warbler in BCR 2.
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 →
Goodnews BayALASKA552005
Salmon LakeALASKA522024
Togiak RiverALASKA422005
NomeALASKA362023
Dillingham (Short)ALASKA241984
CouncilALASKA142024
DillinghamALASKA112019
Kanektok RivALASKA112005
St. Mary'SALASKA52014
TellerALASKA42024
Cape NomeALASKA32017
Gweek RiverALASKA32001
Katmai N.P.ALASKA12013
KotzebueALASKA12022

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