BirdAnalyst
Species · BCR 18 · BBS 2026 Release · 1966–2025

Black-headed Grosbeak In Shortgrass Prairie

All regionsShortgrass PrairieForest birds

Black-headed Grosbeak in Shortgrass Prairie has surged: up 233% on the route-weighted index since 1970.

+233%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 →
39Routes 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 →
53YearsYears 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 increasecomputed 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-headed Grosbeak has surged in Shortgrass Prairie: up 233% on the route-weighted index since 1970.

Black-headed Grosbeak In Shortgrass Prairie Population Forecast

If the recent trend holds, Black-headed Grosbeak in Shortgrass Prairie is projected to stay roughly flat through 2030, near 0.34 (95% range 0.06–0.62). A 5-year backtest shows a typical error of ±59.4%, with 100% of held-out values landing inside the 95% band.

+3%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 →
0.34Projected 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 →
0.06–0.6295% 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 →
±59.4%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-headed Grosbeak in Shortgrass Prairie is projected to stay roughly flat through 2030, near 0.34 (95% range 0.06–0.62). A 5-year backtest shows a typical error of ±59.4%, 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 →
20260.320.040.60
20270.320.040.60
20280.330.050.61
20290.330.050.61
20300.340.060.62

Routes In Shortgrass Prairie

Routes recording Black-headed Grosbeak 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 →
TrincheraCOLORADO102025
Pine RidgeNEBRASKA82025
CrawfordNEBRASKA42024
VillegreenCOLORADO32024
Cone MtnCOLORADO32013
ElbertCOLORADO32025
KiowaCOLORADO22017
Adams Co.COLORADO21998
Kiowa 2COLORADO22025
NinaviewCOLORADO22024
ArsenalCOLORADO22012
LingleWYOMING22014
LamarCOLORADO12023
Gordon CreekCOLORADO11992
BethuneCOLORADO12016
Last Chance 2COLORADO12021
GroverCOLORADO12008
Prospect ValCOLORADO11996
LimonCOLORADO12018
Doyle BridgeCOLORADO11995
NeegrandeCOLORADO12019
Fort MorganCOLORADO12008
KarvalCOLORADO12018
Prospect Valley 2COLORADO12023
Doyle Bridge 2COLORADO12025

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