BirdAnalyst
Species · BCR 18 · BBS 2026 Release · 1966–2025

Brewer's Blackbird In Shortgrass Prairie

All regionsShortgrass PrairieGeneralists

Brewer's Blackbird in Shortgrass Prairie has collapsed: down 87% on the route-weighted index since 1970.

-87%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 →
61Routes 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 declinecomputed 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 →

Brewer's Blackbird has collapsed in Shortgrass Prairie: down 87% on the route-weighted index since 1970.

Brewer's Blackbird In Shortgrass Prairie Population Forecast

If the recent trend holds, Brewer's Blackbird in Shortgrass Prairie is projected to fall about 78% by 2030 — from 0.69 in 2025 to a central estimate of 0.15 (95% range 0.00–3.9). A 5-year backtest shows a typical error of ±35%, with 100% of held-out values landing inside the 95% band.

-78%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 →
0.15Projected 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 →
0.00–3.995% 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 →
±35%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 Shortgrass Prairie is projected to fall about 78% by 2030 — from 0.69 in 2025 to a central estimate of 0.15 (95% range 0.00–3.9). A 5-year backtest shows a typical error of ±35%, 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 →
20260.410.004.1
20270.340.004.1
20280.280.004.0
20290.220.003.9
20300.150.003.9

Routes In Shortgrass Prairie

Routes recording Brewer's Blackbird in Shortgrass Prairie.
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 →
BriggsdaleCOLORADO352008
KiowaCOLORADO292018
FlemingCOLORADO222025
BereaNEBRASKA182017
Kiowa 2COLORADO102023
CrawfordNEBRASKA92019
Pine RidgeNEBRASKA82002
CheyenneWYOMING82025
GilpinCOLORADO71984
BennettCOLORADO72017
ElbertCOLORADO72025
Prospect ValCOLORADO62000
NeegrandeCOLORADO62019
NunnCOLORADO62006
Wagon MoundNEW-MEXICO61971
Cooley LakeNEW-MEXICO61976
PinneoCOLORADO51977
AbarrCOLORADO52023
RushCOLORADO52025
Adams Co.COLORADO52022
VillegreenCOLORADO52000
HardestyOKLAHOMA51988
YoderWYOMING52023
Two ButtesCOLORADO42013
Wildhorse LCOLORADO42015

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