BirdAnalyst
Species · BCR 15 · BBS 2026 Release · 1966–2025

Black-headed Grosbeak In Sierra Nevada

All regionsSierra NevadaForest birds

Black-headed Grosbeak in Sierra Nevada has held roughly steady: up 6% on the route-weighted index since 1970.

+6%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 →
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 →

No notable trend signals for Black-headed Grosbeak in Sierra Nevada. See the full index history below.

Black-headed Grosbeak In Sierra Nevada Population Forecast

If the recent trend holds, Black-headed Grosbeak in Sierra Nevada is projected to rise about 12% by 2030 — from 13 in 2025 to a central estimate of 15 (95% range 5.7–24). A 5-year backtest shows a typical error of ±18.2%, with 100% of held-out values landing inside the 95% band.

+12%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 →
15Projected 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 →
5.7–2495% 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 →
±18.2%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 Nevada is projected to rise about 12% by 2030 — from 13 in 2025 to a central estimate of 15 (95% range 5.7–24). A 5-year backtest shows a typical error of ±18.2%, 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 →
2026155.624
2027155.724
2028155.724
2029155.724
2030155.724

Routes In Sierra Nevada

Routes recording Black-headed Grosbeak in Sierra Nevada.
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 →
PlacervilleCALIFORNIA442025
Forest Hill 2CALIFORNIA372005
Forest HillCALIFORNIA362025
Greenhorn MtCALIFORNIA282008
DownievilleCALIFORNIA282025
PaxtonCALIFORNIA262025
Silver CityCALIFORNIA242013
Eagle LakeCALIFORNIA232025
WestvilleCALIFORNIA172025
Bass LakeCALIFORNIA132019
StrawberryCALIFORNIA132019
Tuolumne GroveCALIFORNIA112025
WawonaCALIFORNIA112025
GeneseeCALIFORNIA102024
CoultervilleCALIFORNIA102019
KernvilleCALIFORNIA102008
Higgins CornCALIFORNIA92025
Pollock PinesCALIFORNIA82025
Butte MeadowCALIFORNIA62014
WoodfordsCALIFORNIA52025
LumberyardCALIFORNIA52025
Tahoe NfCALIFORNIA51994
ChesterCALIFORNIA52017
Meadow ValleyCALIFORNIA52025
ChilcootCALIFORNIA52023

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