BirdAnalyst
Species · BCR 34 · BBS 2026 Release · 1966–2025

Black-headed Grosbeak In Sierra Madre Occidental

All regionsSierra Madre OccidentalForest birds

Black-headed Grosbeak in Sierra Madre Occidental has surged: up 76% on the route-weighted index since 1970.

+76%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 →
34Routes 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 Sierra Madre Occidental: up 76% on the route-weighted index since 1970.

Black-headed Grosbeak In Sierra Madre Occidental Population Forecast

If the recent trend holds, Black-headed Grosbeak in Sierra Madre Occidental is projected to fall about 23% by 2030 — from 6.9 in 2025 to a central estimate of 5.3 (95% range 1.2–9.5). A 5-year backtest shows a typical error of ±18.3%, with 100% of held-out values landing inside the 95% band.

-23%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 →
5.3Projected 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 →
1.2–9.595% 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 →
±18.3%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-headed Grosbeak in Sierra Madre Occidental is projected to fall about 23% by 2030 — from 6.9 in 2025 to a central estimate of 5.3 (95% range 1.2–9.5). A 5-year backtest shows a typical error of ±18.3%, 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 →
20265.41.39.5
20275.41.39.5
20285.41.39.5
20295.41.29.5
20305.31.29.5

Routes In Sierra Madre Occidental

Routes recording Black-headed Grosbeak in Sierra Madre Occidental.
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 →
Tonto Vill.ARIZONA362025
PortalARIZONA242025
WilliamsARIZONA222025
Mt. GrahamARIZONA172025
Aztec PeakARIZONA131978
Emory PassNEW-MEXICO132025
ReserveNEW-MEXICO112025
PatagoniaARIZONA102025
PrescottARIZONA82025
Skull Valley 2ARIZONA82025
PinetopARIZONA62022
RedingtonARIZONA62025
Happy JackARIZONA62025
RuckerARIZONA62009
DragoonARIZONA52009
Mormon LakeARIZONA41975
CutterARIZONA42014
AlpineARIZONA42025
Sunizona 2ARIZONA42025
PomereneARIZONA32024
Peña BlancaARIZONA32025
SunizonaARIZONA31997
MaineARIZONA32025
Forest LakesARIZONA32025
SprucedaleARIZONA32025

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