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

Orange-crowned Warbler In BCR 4

All regionsBCR 4Forest birds

Orange-crowned Warbler in BCR 4 has risen sharply: up 70% on the route-weighted index since 1978.

+70%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 →

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 →

Orange-crowned Warbler has risen sharply in BCR 4: up 70% on the route-weighted index since 1978.

Orange-crowned Warbler In BCR 4 Population Forecast

If the recent trend holds, Orange-crowned Warbler in BCR 4 is projected to rise about 41% by 2029 — from 15 in 2024 to a central estimate of 21 (95% range 14–28). A 5-year backtest shows a typical error of ±40.4%, with 20% of held-out values landing inside the 95% band.

+41%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 →
21Projected 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 →
14–2895% 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 →
±40.4%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, Orange-crowned Warbler in BCR 4 is projected to rise about 41% by 2029 — from 15 in 2024 to a central estimate of 21 (95% range 14–28). A 5-year backtest shows a typical error of ±40.4%, with 20% 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 →
2025211328
2026211428
2027211428
2028211428
2029211428

Routes In BCR 4

Routes recording Orange-crowned 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 →
Kanuti CanynALASKA572024
SavageALASKA552024
HomerALASKA521982
ToklatALASKA512024
Unalakleet RiverALASKA372022
CohoeALASKA342023
Anchor RiverALASKA332024
KachemakALASKA322024
KalifonskyALASKA292023
CottonwoodALASKA281990
Moose CreekALASKA272022
Hatcher PassALASKA262024
NorthwayALASKA252023
MonahanALASKA232021
Burma RoadALASKA222024
KuskulanaALASKA222024
Chena RiverALASKA211988
RubyALASKA212024
DeltaALASKA192024
MatanuskaALASKA181983
L SalchaALASKA182023
EagleALASKA172024
Kenny LakeALASKA172024
TatalinaALASKA172019
Galena (Short)ALASKA172024

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