BirdAnalyst
Species · BCR 16 · BBS 2026 Release · 1966–2025

Brewer's Blackbird In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauGeneralists

Brewer's Blackbird in Southern Rockies / Colorado Plateau has declined: down 35% on the route-weighted index since 1970.

-35%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 →
193Routes 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 Brewer's Blackbird in Southern Rockies / Colorado Plateau. See the full index history below.

Brewer's Blackbird In Southern Rockies / Colorado Plateau Population Forecast

If the recent trend holds, Brewer's Blackbird in Southern Rockies / Colorado Plateau is projected to fall about 55% by 2030 — from 7.3 in 2025 to a central estimate of 3.3 (95% range 0.00–17). A 5-year backtest shows a typical error of ±34.3%, with 100% of held-out values landing inside the 95% band.

-55%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 →
3.3Projected 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 →
0.00–1795% 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 →
±34.3%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, Brewer's Blackbird in Southern Rockies / Colorado Plateau is projected to fall about 55% by 2030 — from 7.3 in 2025 to a central estimate of 3.3 (95% range 0.00–17). A 5-year backtest shows a typical error of ±34.3%, 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 →
20264.90.0018
20274.50.0018
20284.10.0018
20293.70.0017
20303.30.0017

Routes In Southern Rockies / Colorado Plateau

Routes recording Brewer's Blackbird 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 →
YampaCOLORADO1042023
KamasUTAH832025
AlamosaCOLORADO582025
Pagosa SpgsCOLORADO561982
DoloresCOLORADO551987
BufordWYOMING512025
Angel FireNEW-MEXICO472002
Ant Flat-Ogden CanUTAH392025
GuffeyCOLORADO352025
Black Sulphur CrCOLORADO352025
Sybille CynWYOMING352025
Yellowjacket PassCOLORADO332025
Angel Fire 2NEW-MEXICO322025
CastletonCOLORADO312025
BufordCOLORADO302025
DinosaurCOLORADO282025
PowderhornCOLORADO272025
Cochetopa PassCOLORADO272025
M Warner ResUTAH272025
Fletcher PkWYOMING252025
Colona 2COLORADO242025
Alton 2UTAH242025
CokedaleCOLORADO232025
Steamboat L.COLORADO232025
Stinking Lk.NEW-MEXICO231999

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