BirdAnalyst
Species · BCR 10 · BBS 2026 Release · 1966–2025

Black-billed Magpie In Northern Rockies

All regionsNorthern RockiesGeneralists

Black-billed Magpie in Northern Rockies has declined: down 37% on the route-weighted index since 1970.

-37%Since 1970TrendPercent 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 →
182Routes 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 →
57YearsYears 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 Black-billed Magpie in Northern Rockies. See the full index history below.

Black-billed Magpie In Northern Rockies Population Forecast

If the recent trend holds, Black-billed Magpie in Northern Rockies is projected to fall about 23% by 2030 — from 8.7 in 2025 to a central estimate of 6.7 (95% range 0.63–13). A 5-year backtest shows a typical error of ±37.4%, with 100% of held-out values landing inside the 95% band.

-23%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 →
6.7Projected 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 →
0.63–1395% 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 →
±37.4%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, Black-billed Magpie in Northern Rockies is projected to fall about 23% by 2030 — from 8.7 in 2025 to a central estimate of 6.7 (95% range 0.63–13). A 5-year backtest shows a typical error of ±37.4%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20267.00.9613
20276.90.8813
20286.80.8013
20296.80.7113
20306.70.6313

Routes In Northern Rockies

Routes recording Black-billed Magpie in Northern Rockies.
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 →
BoulderWYOMING962025
Clyde ParkMONTANA702025
ChestnutMONTANA692025
CarterWYOMING682016
Summit PrOREGON512025
Willow Creek 2MONTANA492025
Green RiverWYOMING441984
Heart ButteMONTANA392025
ChewelahWASHINGTON392021
MeeteetseWYOMING372025
GlenMONTANA352025
SpartaOREGON332025
RiversideWYOMING322025
VictorMONTANA282025
CodyWYOMING272025
LovellWYOMING272025
PolsonMONTANA262025
Church HillMONTANA252025
Cramer CreekMONTANA252016
Willow CreekMONTANA241981
Pablo Res.MONTANA242025
NewbridgeOREGON242025
LeoWYOMING232025
KalispellMONTANA222025
BeaverheadMONTANA222025

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