BirdAnalyst
Species · BCR 15 · BBS 2025 Release · 1966–2024

Black-headed Grosbeak In Sierra Nevada

All regionsSierra NevadaGeneralists

Black-headed Grosbeak in Sierra Nevada has edged up: up 16% on the route-weighted index since 1970.

+16%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 →
56YearsYears 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 37% by 2029 — from 11 in 2024 to a central estimate of 15 (95% range 5.7–24). A 5-year backtest shows a typical error of ±18.5%, with 100% of held-out values landing inside the 95% band.

+37%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 →
15Projected 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 →
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 →
±18.5%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 Sierra Nevada is projected to rise about 37% by 2029 — from 11 in 2024 to a central estimate of 15 (95% range 5.7–24). A 5-year backtest shows a typical error of ±18.5%, with 100% of held-out values landing inside the 95% band.19682029
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 →
2025155.624
2026155.724
2027155.724
2028155.724
2029155.724

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 →
PlacervilleCALIFORNIA592024
Forest HillCALIFORNIA502022
Forest Hill 2CALIFORNIA372005
Greenhorn MtCALIFORNIA282008
DownievilleCALIFORNIA272024
Silver CityCALIFORNIA242013
PaxtonCALIFORNIA222024
Eagle LakeCALIFORNIA172024
WawonaCALIFORNIA162024
Bass LakeCALIFORNIA132019
Pollock PinesCALIFORNIA132024
StrawberryCALIFORNIA132019
GeneseeCALIFORNIA102024
CoultervilleCALIFORNIA102019
KernvilleCALIFORNIA102008
WestvilleCALIFORNIA72024
Higgins CornCALIFORNIA72024
Butte MeadowCALIFORNIA62014
RivertonCALIFORNIA62023
Tuolumne GroveCALIFORNIA52024
Tahoe NfCALIFORNIA51994
ChesterCALIFORNIA52017
ChilcootCALIFORNIA52023
Lassen ParkCALIFORNIA41989
LumberyardCALIFORNIA42024

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