BirdAnalyst
Species · BCR 10 · BBS 2026 Release · 1966–2025

Black-headed Grosbeak In Northern Rockies

All regionsNorthern RockiesForest birds

Black-headed Grosbeak in Northern Rockies has surged: up 356% on the route-weighted index since 1970.

+356%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 →
166Routes 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 Northern Rockies: up 356% on the route-weighted index since 1970.

Black-headed Grosbeak In Northern Rockies Population Forecast

If the recent trend holds, Black-headed Grosbeak in Northern Rockies is projected to rise about 12% by 2030 — from 1.6 in 2025 to a central estimate of 1.7 (95% range 1.3–2.2). A 5-year backtest shows a typical error of ±12.3%, 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 →
1.7Projected 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 →
1.3–2.295% 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 →
±12.3%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 Northern Rockies is projected to rise about 12% by 2030 — from 1.6 in 2025 to a central estimate of 1.7 (95% range 1.3–2.2). A 5-year backtest shows a typical error of ±12.3%, 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 →
20261.71.22.2
20271.71.22.2
20281.71.22.2
20291.71.22.2
20301.71.32.2

Routes In Northern Rockies

Routes recording Black-headed Grosbeak in Northern Rockies.
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 →
SpartaOREGON221999
LaurierWASHINGTON152025
WilsonWYOMING152025
CentervilleIDAHO142025
NaplesIDAHO112025
CascadeIDAHO111984
Black Mtn.OREGON102004
Donelly 2OREGON82025
KellerWASHINGTON82007
WoodmanMONTANA72025
NinemileMONTANA72025
TroyOREGON72025
Spring LakeWASHINGTON72025
Bald MtnWYOMING72007
Rochat DivdeIDAHO62025
ClintonMONTANA62024
BridgeportOREGON62025
NewbridgeOREGON62025
ChewelahWASHINGTON62021
MooseWYOMING62025
Lolo PassIDAHO52019
ChallisIDAHO52025
Baldy MountainIDAHO52016
PierceIDAHO52005
FeathervilleIDAHO52025

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