BirdAnalyst
Species · BCR 16 · BBS 2026 Release · 1966–2025

Black-headed Grosbeak In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauForest birds

Black-headed Grosbeak in Southern Rockies / Colorado Plateau has surged: up 121% on the route-weighted index since 1970.

+121%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 →
196Routes 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 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 Southern Rockies / Colorado Plateau: up 121% on the route-weighted index since 1970.

Black-headed Grosbeak In Southern Rockies / Colorado Plateau Population Forecast

If the recent trend holds, Black-headed Grosbeak in Southern Rockies / Colorado Plateau is projected to fall about 14% by 2030 — from 3.9 in 2025 to a central estimate of 3.4 (95% range 2.5–4.2). A 5-year backtest shows a typical error of ±12.5%, with 100% of held-out values landing inside the 95% band.

-14%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 →
3.4Projected 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 →
2.5–4.295% 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 →
±12.5%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, Black-headed Grosbeak in Southern Rockies / Colorado Plateau is projected to fall about 14% by 2030 — from 3.9 in 2025 to a central estimate of 3.4 (95% range 2.5–4.2). A 5-year backtest shows a typical error of ±12.5%, 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 →
20263.22.44.1
20273.32.44.1
20283.32.54.2
20293.32.54.2
20303.42.54.2

Routes In Southern Rockies / Colorado Plateau

Routes recording Black-headed Grosbeak 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 →
WalsenburgCOLORADO592025
Mesaverde NpCOLORADO452025
GallinasNEW-MEXICO372025
Angel Fire 2NEW-MEXICO242025
CokedaleCOLORADO212025
AnimasCOLORADO212004
Mcphee Res.COLORADO202025
Dry ParkARIZONA182025
Blackhead PkCOLORADO172025
Ojo SarcoNEW-MEXICO172025
GooseberryUTAH142025
Claunch 2NEW-MEXICO132025
Douglas PassCOLORADO122024
Wilson CreekCOLORADO122025
Baxter PassCOLORADO122024
Mt. Taylor 2NEW-MEXICO112024
Main CanyonUTAH112025
ZeniffARIZONA101973
TsaileARIZONA102023
Wet Mtns.COLORADO102025
Animas 2COLORADO92025
Ant Flat-Ogden CanUTAH92025
La Sal 2UTAH92006
PaoniaCOLORADO82025
Rifle FallsCOLORADO82025

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