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Species · BCR 4 · BBS 2026 Release · 1966–2025

Yellow-bellied Flycatcher In BCR 4

All regionsBCR 4Aerial insectivores

Yellow-bellied Flycatcher in BCR 4 has surged: up 21× on the route-weighted index since 1996.

21×Since 1996TrendPercent 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 →
29YearsYears 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 Yellow-bellied Flycatcher in BCR 4. See the full index history below.

Yellow-bellied Flycatcher In BCR 4 Population Forecast

If the recent trend holds, Yellow-bellied Flycatcher in BCR 4 is projected to fall about 19% by 2030 — from 0.97 in 2025 to a central estimate of 0.79 (95% range 0.53–1.0). A 5-year backtest shows a typical error of ±43.1%, with 0% of held-out values landing inside the 95% band.

-19%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 →
0.79Projected 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 →
0.53–1.095% 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 →
±43.1%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, Yellow-bellied Flycatcher in BCR 4 is projected to fall about 19% by 2030 — from 0.97 in 2025 to a central estimate of 0.79 (95% range 0.53–1.0). A 5-year backtest shows a typical error of ±43.1%, with 0% of held-out values landing inside the 95% band.19942030
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 →
20260.690.440.95
20270.720.460.97
20280.740.480.99
20290.760.511.0
20300.790.531.0

Routes In BCR 4

Routes recording Yellow-bellied Flycatcher 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 →
EagleALASKA142025
Mt. FairplayALASKA132025
ChickenALASKA62025
Chatanika RALASKA32025
Birch LakeALASKA22019
MonahanALASKA22010
Kanuti CanynALASKA22024
LivengoodALASKA12021
SlanaALASKA12017
Tower BluffsALASKA12022
NorthwayALASKA12019
SourdoughALASKA11995
Kanuti LakeALASKA12013
Nabesna RoadALASKA12014

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