BirdAnalyst
Species · BCR 33 · BBS 2025 Release · 1966–2024

Black-headed Grosbeak In Sonoran and Mojave Deserts

All regionsSonoran and Mojave DesertsGeneralists

Black-headed Grosbeak in Sonoran and Mojave Deserts has declined: down 36% on the route-weighted index since 1971.

-36%Since 1971TrendPercent 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 →
18Routes 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 →
55YearsYears 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 →

No notable trend signals for Black-headed Grosbeak in Sonoran and Mojave Deserts. See the full index history below.

Black-headed Grosbeak In Sonoran and Mojave Deserts Population Forecast

If the recent trend holds, Black-headed Grosbeak in Sonoran and Mojave Deserts is projected to fall about 14% by 2029 — from 0.17 in 2024 to a central estimate of 0.14 (95% range 0.00–0.44). A 5-year backtest shows a typical error of ±106.1%, with 100% of held-out values landing inside the 95% band.

-14%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 →
0.14Projected 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 →
0.00–0.4495% 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 →
±106.1%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-headed Grosbeak in Sonoran and Mojave Deserts is projected to fall about 14% by 2029 — from 0.17 in 2024 to a central estimate of 0.14 (95% range 0.00–0.44). A 5-year backtest shows a typical error of ±106.1%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20250.160.000.45
20260.150.000.45
20270.150.000.45
20280.150.000.44
20290.140.000.44

Routes In Sonoran and Mojave Deserts

Routes recording Black-headed Grosbeak in Sonoran and Mojave Deserts.
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 →
NilandCALIFORNIA42023
Kelso ValleyCALIFORNIA42024
Willow SpgsCALIFORNIA21971
Coachella CnCALIFORNIA22000
CimaCALIFORNIA21974
Cholla Gard.CALIFORNIA21995
Red RockARIZONA12008
OnyxCALIFORNIA11994
BarstowCALIFORNIA11997
Anza BorregoCALIFORNIA12024
InyokernCALIFORNIA12007
LenwoodCALIFORNIA11982
IvanpahCALIFORNIA11996
TecopaCALIFORNIA12015
CottonwoodCALIFORNIA11976
Imperial DamCALIFORNIA11984
PearblossomCALIFORNIA12017
Lone PineCALIFORNIA12005

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