BirdAnalyst
Species · BCR 2 · BBS 2026 Release · 1966–2025

Black-billed Magpie In BCR 2

All regionsBCR 2Generalists

Black-billed Magpie in BCR 2 has fallen sharply: down 74% on the route-weighted index since 1985.

-74%Since 1985TrendPercent 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 →
11Routes 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 →
42YearsYears 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 →

Black-billed Magpie has fallen sharply in BCR 2: down 74% on the route-weighted index since 1985.

Black-billed Magpie In BCR 2 Population Forecast

If the recent trend holds, Black-billed Magpie in BCR 2 is projected to fall about 99% by 2030 — from 2.8 in 2025 to a central estimate of 0.04 (95% range 0.00–6.1). A 5-year backtest shows a typical error of ±101.9%, with 100% of held-out values landing inside the 95% band.

-99%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 →
0.04Projected 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 →
0.00–6.195% 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 →
±101.9%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, Black-billed Magpie in BCR 2 is projected to fall about 99% by 2030 — from 2.8 in 2025 to a central estimate of 0.04 (95% range 0.00–6.1). A 5-year backtest shows a typical error of ±101.9%, with 100% of held-out values landing inside the 95% band.19832030
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 →
20260.720.006.8
20270.550.006.6
20280.380.006.4
20290.210.006.3
20300.040.006.1

Routes In BCR 2

Routes recording Black-billed Magpie 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 →
KodiakALASKA141984
Kodiak 2ALASKA92025
ChiniakALASKA52025
DillinghamALASKA52017
Cold BayALASKA22025
Goodnews BayALASKA22005
Cold Bay (Short)ALASKA21992
Katmai N.P.ALASKA12025
King SalmonALASKA12023
Togiak RiverALASKA12005
Kanektok RivALASKA12003

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