BirdAnalyst
Species · BCR 9 · BBS 2026 Release · 1966–2025

Black-billed Magpie In Great Basin

All regionsGreat BasinGeneralists

Black-billed Magpie in Great Basin has declined: down 45% on the route-weighted index since 1970.

-45%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 →
210Routes 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 Great Basin. See the full index history below.

Black-billed Magpie In Great Basin Population Forecast

If the recent trend holds, Black-billed Magpie in Great Basin is projected to rise about 34% by 2030 — from 5.6 in 2025 to a central estimate of 7.5 (95% range 4.0–11). A 5-year backtest shows a typical error of ±43.4%, with 100% of held-out values landing inside the 95% band.

+34%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 →
7.5Projected 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 →
4.0–1195% 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 →
±43.4%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 Great Basin is projected to rise about 34% by 2030 — from 5.6 in 2025 to a central estimate of 7.5 (95% range 4.0–11). A 5-year backtest shows a typical error of ±43.4%, 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 →
20267.74.311
20277.74.311
20287.64.211
20297.54.111
20307.54.011

Routes In Great Basin

Routes recording Black-billed Magpie in Great Basin.
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 →
PocatelloIDAHO1102019
MesaWASHINGTON902008
LeadoreIDAHO792024
Cedar HillIDAHO712024
Toiyabe NfNEVADA602024
OthelloWASHINGTON591991
OrdnanceOREGON581979
YakimaWASHINGTON562025
Gardnerville 2NEVADA552025
SpringfieldIDAHO542018
BakerIDAHO452024
BatesIDAHO432023
Modoc PointOREGON362018
MacdoelCALIFORNIA352019
HarwoodWASHINGTON341997
Mud LakeIDAHO312025
FallonNEVADA282025
Modoc Point 2OREGON272025
RirieIDAHO262025
GardnervilleNEVADA262012
DeschutesOREGON252025
PrestonIDAHO242023
Walla WallaWASHINGTON241993
JosephOREGON232025
MerrillOREGON232022

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