BirdAnalyst
Species · BCR 16 · BBS 2025 Release · 1966–2024

Blue Grosbeak In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauGeneralists

Blue Grosbeak in Southern Rockies / Colorado Plateau has surged: up 168% on the route-weighted index since 1970.

+168%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 →
112Routes 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 →

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 Southern Rockies / Colorado Plateau: up 168% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Blue Grosbeak in Southern Rockies / Colorado Plateau is projected to fall about 41% by 2029 — from 0.75 in 2024 to a central estimate of 0.45 (95% range 0.00–0.89). A 5-year backtest shows a typical error of ±22.5%, with 100% of held-out values landing inside the 95% band.

-41%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 →
0.45Projected 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 →
0.00–0.8995% 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 →
±22.5%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, Blue Grosbeak in Southern Rockies / Colorado Plateau is projected to fall about 41% by 2029 — from 0.75 in 2024 to a central estimate of 0.45 (95% range 0.00–0.89). A 5-year backtest shows a typical error of ±22.5%, 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 →
20250.460.020.90
20260.460.010.90
20270.450.010.90
20280.450.010.89
20290.450.000.89

Routes In Southern Rockies / Colorado Plateau

Routes recording Blue Grosbeak in Southern Rockies / Colorado Plateau.
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 →
TsaileARIZONA371995
Douglas PassCOLORADO132024
AnethUTAH122024
DoloresCOLORADO91982
MountainairNEW-MEXICO92024
CokedaleCOLORADO72024
ValenciaNEW-MEXICO61997
HuntARIZONA51990
Baxter PassCOLORADO52024
CounselorNEW-MEXICO52024
Angel Fire 2NEW-MEXICO52024
CastletonUTAH51985
Peach SpringARIZONA42022
De BequeCOLORADO42024
Animas 2COLORADO42021
AztecNEW-MEXICO41989
Moquith MtnUTAH42024
SeligmanARIZONA32021
Wray GulchCOLORADO32021
PaoniaCOLORADO32024
WalsenburgCOLORADO32024
GallinasNEW-MEXICO32021
Bullfrog BayUTAH32008
FalfaCOLORADO22024
San LuisCOLORADO22024

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