BirdAnalyst
Species · BCR 18 · BBS 2025 Release · 1966–2024

Black-billed Magpie In Shortgrass Prairie

All regionsShortgrass PrairieGeneralists

Black-billed Magpie in Shortgrass Prairie has fallen sharply: down 60% on the route-weighted index since 1969.

-60%Since 1969TrendPercent 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 →
67Routes 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 →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Black-billed Magpie has fallen sharply in Shortgrass Prairie: down 60% on the route-weighted index since 1969.

Black-billed Magpie In Shortgrass Prairie Population Forecast

If the recent trend holds, Black-billed Magpie in Shortgrass Prairie is projected to fall about 41% by 2029 — from 0.96 in 2024 to a central estimate of 0.57 (95% range 0.00–2.0). A 5-year backtest shows a typical error of ±27.1%, with 100% of held-out values landing inside the 95% band.

-41%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 →
0.57Projected 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 →
0.00–2.095% 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 →
±27.1%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 Shortgrass Prairie is projected to fall about 41% by 2029 — from 0.96 in 2024 to a central estimate of 0.57 (95% range 0.00–2.0). A 5-year backtest shows a typical error of ±27.1%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.700.002.2
20260.670.002.1
20270.640.002.1
20280.600.002.1
20290.570.002.0

Routes In Shortgrass Prairie

Routes recording Black-billed Magpie in Shortgrass Prairie.
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 →
Doyle BridgeCOLORADO301997
Prospect ValCOLORADO252000
ElbertCOLORADO252024
ArsenalCOLORADO192015
Doyle Bridge 2COLORADO152023
CrawfordNEBRASKA142024
Pine RidgeNEBRASKA142024
VillegreenCOLORADO132006
NinaviewCOLORADO112001
KimballNEBRASKA111978
DaltonNEBRASKA82024
Arsenal 2COLORADO72024
Fort MorganCOLORADO52021
ClovisNEW-MEXICO52001
GilpinCOLORADO42024
Wildhorse LCOLORADO42000
BriggsdaleCOLORADO32005
Last ChanceCOLORADO31989
Adams Co.COLORADO32022
TrincheraCOLORADO32021
GroverCOLORADO32024
BrownsonNEBRASKA32021
FarleyNEW-MEXICO32014
Pine BluffWYOMING31993
PinneoCOLORADO22010

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