BirdAnalyst
Species · BCR 32 · BBS 2026 Release · 1966–2025

Yellow-billed Magpie In Coastal California

All regionsCoastal CaliforniaGeneralists

Yellow-billed Magpie in Coastal California has edged down: down 25% on the route-weighted index since 1970.

-25%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 →
47Routes 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 Yellow-billed Magpie in Coastal California. See the full index history below.

Yellow-billed Magpie In Coastal California Population Forecast

If the recent trend holds, Yellow-billed Magpie in Coastal California is projected to stay roughly flat through 2030, near 4.3 (95% range 0.00–9.9). A 5-year backtest shows a typical error of ±77.5%, with 100% of held-out values landing inside the 95% band.

+1%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 →
4.3Projected 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 →
0.00–9.995% 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 →
±77.5%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, Yellow-billed Magpie in Coastal California is projected to stay roughly flat through 2030, near 4.3 (95% range 0.00–9.9). A 5-year backtest shows a typical error of ±77.5%, 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 →
20264.70.0010
20274.60.0010
20284.50.0010
20294.40.0010
20304.30.009.9

Routes In Coastal California

Routes recording Yellow-billed Magpie in Coastal California.
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 →
CollegevilleCALIFORNIA462004
AtwaterCALIFORNIA402004
Tres Pinos 2CALIFORNIA362011
ZamoraCALIFORNIA332025
GreenfieldCALIFORNIA232025
AthloneCALIFORNIA212004
AdelaidaCALIFORNIA202025
JacksonCALIFORNIA201992
GlennCALIFORNIA172025
HughsonCALIFORNIA162025
WestleyCALIFORNIA142025
Collegeville 2CALIFORNIA132023
Tres PinosCALIFORNIA112003
CrestonCALIFORNIA102024
CohassetCALIFORNIA92025
ReddingCALIFORNIA91983
LockwoodCALIFORNIA92025
CordovaCALIFORNIA81981
Ora LomaCALIFORNIA81995
Carmel ValCALIFORNIA72025
RumseyCALIFORNIA62008
OnealsCALIFORNIA62005
Staten Is.CALIFORNIA62025
TomheadCALIFORNIA62011
Yolla BollyCALIFORNIA52023

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