BirdAnalyst
Species · BCR 16 · BBS 2025 Release · 1966–2024

Black-billed Magpie In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauGeneralists

Black-billed Magpie in Southern Rockies / Colorado Plateau has edged down: down 11% on the route-weighted index since 1970.

-11%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 →
180Routes 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 Southern Rockies / Colorado Plateau. See the full index history below.

Black-billed Magpie In Southern Rockies / Colorado Plateau Population Forecast

If the recent trend holds, Black-billed Magpie in Southern Rockies / Colorado Plateau is projected to fall about 31% by 2029 — from 7.3 in 2024 to a central estimate of 5.1 (95% range 0.00–11). A 5-year backtest shows a typical error of ±20.3%, with 100% of held-out values landing inside the 95% band.

-31%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 →
5.1Projected 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 →
0.00–1195% 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 →
±20.3%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 Southern Rockies / Colorado Plateau is projected to fall about 31% by 2029 — from 7.3 in 2024 to a central estimate of 5.1 (95% range 0.00–11). A 5-year backtest shows a typical error of ±20.3%, 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 →
20255.60.0011
20265.50.0011
20275.30.0011
20285.20.0011
20295.10.0011

Routes In Southern Rockies / Colorado Plateau

Routes recording Black-billed Magpie in Southern Rockies / Colorado Plateau.
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 →
YampaCOLORADO1102023
HannaUTAH742024
KamasUTAH572024
AztecNEW-MEXICO541989
BufordCOLORADO452024
CastletonCOLORADO432024
Yellowjacket PassCOLORADO412024
FarmingtonNEW-MEXICO411987
AspenCOLORADO392024
Douglas PassCOLORADO362024
Stinking Lk.NEW-MEXICO351999
Deadman Rd.COLORADO322024
De BequeCOLORADO312024
Ojo SarcoNEW-MEXICO292024
Wilson CreekCOLORADO242024
Moon Lake 2UTAH242023
Rifle FallsCOLORADO232021
PaoniaCOLORADO222024
PowderhornCOLORADO222023
MoffatCOLORADO212024
Mcphee Res.COLORADO202024
DoloresCOLORADO191987
Fox CreekCOLORADO192024
AltonahUTAH192015
Hill CreekUTAH191995

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