BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

Black-billed Magpie In Great Basin

All regionsGreat BasinGeneralists

Black-billed Magpie in Great Basin has declined: down 44% on the route-weighted index since 1970.

-44%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 →
56YearsYears 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 16% by 2029 — from 6.6 in 2024 to a central estimate of 7.7 (95% range 4.3–11). A 5-year backtest shows a typical error of ±32.3%, with 100% of held-out values landing inside the 95% band.

+16%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 →
7.7Projected 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 →
4.3–1195% 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 →
±32.3%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 16% by 2029 — from 6.6 in 2024 to a central estimate of 7.7 (95% range 4.3–11). A 5-year backtest shows a typical error of ±32.3%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20258.04.611
20267.94.511
20277.84.511
20287.84.411
20297.74.311

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
PicaboIDAHO652021
Toiyabe NfNEVADA602024
OthelloWASHINGTON591991
OrdnanceOREGON581979
Chimney Res.NEVADA552024
SpringfieldIDAHO542018
BakerIDAHO452024
BatesIDAHO432023
FallonNEVADA412024
YakimaWASHINGTON372024
Modoc PointOREGON362018
MacdoelCALIFORNIA352019
NighthawkWASHINGTON352024
Trout CreekOREGON342021
HarwoodWASHINGTON341997
AdrianOREGON312021
GardnervilleNEVADA262012
Modoc Point 2OREGON262024
CedarvilleCALIFORNIA242024
PrestonIDAHO242023
DeschutesOREGON242024

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