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

Red-winged Blackbird In BCR 4

All regionsBCR 4Generalists

Red-winged Blackbird in BCR 4 has fallen sharply: down 55% on the route-weighted index since 1994.

-55%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 →
6Routes 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 →
21YearsYears 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 declinecomputed 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 →

Red-winged Blackbird has fallen sharply in BCR 4: down 55% on the route-weighted index since 1994.

Forecast

If the recent trend holds, Red-winged Blackbird in BCR 4 is projected to fall about 71% by 2029 — from 0.06 in 2024 to a central estimate of 0.02 (95% range 0.00–0.10). A 5-year backtest shows a typical error of ±37.2%, with 100% of held-out values landing inside the 95% band.

-71%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 →
0.02Projected 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 →
0.00–0.1095% 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 →
±37.2%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, Red-winged Blackbird in BCR 4 is projected to fall about 71% by 2029 — from 0.06 in 2024 to a central estimate of 0.02 (95% range 0.00–0.10). A 5-year backtest shows a typical error of ±37.2%, with 100% of held-out values landing inside the 95% band.19872029
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 →
20250.020.000.11
20260.020.000.11
20270.020.000.10
20280.020.000.10
20290.020.000.10

Routes In BCR 4

Routes recording Red-winged Blackbird 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 →
SlanaALASKA22024
Ft. RichrdsnALASKA22006
ChistochinaALASKA11997
NorthwayALASKA12003
L SalchaALASKA12023
Kenny LakeALASKA12003

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