BirdAnalyst
Species · BCR 10 · BBS 2025 Release · 1966–2024

Blue Grosbeak In Northern Rockies

All regionsNorthern RockiesGeneralists

Blue Grosbeak in Northern Rockies has surged: up 333% on the route-weighted index since 1992.

+333%Since 1992TrendPercent 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 →
11Routes 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 →
19YearsYears 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 →

Blue Grosbeak has surged in Northern Rockies: up 333% on the route-weighted index since 1992.

Blue Grosbeak In Northern Rockies Population Forecast

If the recent trend holds, Blue Grosbeak in Northern Rockies is projected to fall about 30% by 2029 — from 0.06 in 2024 to a central estimate of 0.04 (95% range 0.01–0.07). A 5-year backtest shows a typical error of ±70.6%, with 20% of held-out values landing inside the 95% band.

-30%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 →
0.04Projected 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 →
0.01–0.0795% 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 →
±70.6%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, Blue Grosbeak in Northern Rockies is projected to fall about 30% by 2029 — from 0.06 in 2024 to a central estimate of 0.04 (95% range 0.01–0.07). A 5-year backtest shows a typical error of ±70.6%, with 20% of held-out values landing inside the 95% band.19872029
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 →
20250.040.010.06
20260.040.010.07
20270.040.010.07
20280.040.010.07
20290.040.010.07

Routes In Northern Rockies

Routes recording Blue 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 →
OttoWYOMING52024
MidvaleWYOMING32017
EtheteWYOMING22023
GeboWYOMING22015
MaybellCOLORADO12017
Browns ParkCOLORADO12024
LayCOLORADO12022
LaurelMONTANA12022
BasinWYOMING12024
TensleepWYOMING12024
Mtn ViewWYOMING12023

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