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Species · Arizona · BBS 2026 Release · 1966–2025

Black-headed Grosbeak Population Trend in Arizona

All statesForest birds

Black-headed Grosbeak in Arizona has surged: up 123% on the route-weighted index since 1970.

+123%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 →
45Routes In StateSurvey 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 Black-headed Grosbeak Trends in ArizonaNotable 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 Arizona: up 123% on the route-weighted index since 1970.

Black-headed Grosbeak Population Forecast in Arizona

If the recent trend holds, Black-headed Grosbeak in Arizona is projected to fall about 42% by 2030 — from 4.4 in 2025 to a central estimate of 2.6 (95% range 0.30–4.8). A 5-year backtest shows a typical error of ±17.7%, with 100% of held-out values landing inside the 95% band.

-42%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 →
2.6Projected 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 →
0.30–4.895% 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 →
±17.7%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 Arizona is projected to fall about 42% by 2030 — from 4.4 in 2025 to a central estimate of 2.6 (95% range 0.30–4.8). A 5-year backtest shows a typical error of ±17.7%, 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 →
20262.60.354.9
20272.60.344.8
20282.60.334.8
20292.60.324.8
20302.60.304.8

Black-headed Grosbeak Survey Routes in Arizona

Routes recording Black-headed Grosbeak in Arizona.
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.3620251994
Portal2420251975
Williams2220251999
Dry Park1820251992
Mt. Graham1720251995
Aztec Peak1319781974
Zeniff1019731968
Patagonia1020251968
Tsaile1020231995
Prescott820251974
Skull Valley 2820252025
Rucker620091993
Pinetop620221993
Redington620251999
Happy Jack620251992
Dragoon520091993
Mormon Lake419751968
Cutter420142014
Alpine420252004
Sunizona 2420252001
Yampai319711971
Hunt319761976
Pomerene320241974
Peña Blanca320251977
Sunizona319971968

Black-headed Grosbeak Population Trend in Other States

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