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

Blackpoll Warbler In BCR 4

All regionsBCR 4Forest birds

Blackpoll Warbler in BCR 4 has risen sharply: up 57% on the route-weighted index since 1976.

+57%Since 1976TrendPercent 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 →
60Routes 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 →
47YearsYears 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 →

Blackpoll Warbler has risen sharply in BCR 4: up 57% on the route-weighted index since 1976.

Forecast

If the recent trend holds, Blackpoll Warbler in BCR 4 is projected to rise about 61% by 2029 — from 3.3 in 2024 to a central estimate of 5.2 (95% range 0.88–9.6). A 5-year backtest shows a typical error of ±87.9%, with 100% of held-out values landing inside the 95% band.

+61%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 →
5.2Projected 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 →
0.88–9.695% 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 →
±87.9%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, Blackpoll Warbler in BCR 4 is projected to rise about 61% by 2029 — from 3.3 in 2024 to a central estimate of 5.2 (95% range 0.88–9.6). A 5-year backtest shows a typical error of ±87.9%, 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 →
20255.20.859.6
20265.20.869.6
20275.20.879.6
20285.20.879.6
20295.20.889.6

Routes In BCR 4

Routes recording Blackpoll 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 →
Goose BayALASKA331982
Mud RiverALASKA282024
Skilak LakeALASKA211985
MonahanALASKA182021
WasillaALASKA181983
Hather CreekALASKA172024
CantwellALASKA142021
KalifonskyALASKA141982
HomerALASKA121982
SavageALASKA122024
Galena (Short)ALASKA102024
CircleALASKA72018
MatanuskaALASKA71983
Caribou Mtn.ALASKA72021
SourdoughALASKA62024
MaclarenALASKA52024
WillowALASKA52024
Unalakleet RiverALASKA52024
Mt. FairplayALASKA52016
Anvik RiverALASKA52024
TatalinaALASKA52019
Kobuk River (Short)ALASKA51992
Chatanika RALASKA42019
Swan Lake RdALASKA42017
Lake LouiseALASKA42014

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