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

Brewer's Blackbird In Northern Rockies

All regionsNorthern RockiesGeneralists

Brewer's Blackbird in Northern Rockies has fallen sharply: down 62% on the route-weighted index since 1970.

-62%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 →
206Routes 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 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 fallen sharply in Northern Rockies: down 62% on the route-weighted index since 1970.

Brewer's Blackbird In Northern Rockies Population Forecast

If the recent trend holds, Brewer's Blackbird in Northern Rockies is projected to fall about 47% by 2030 — from 12 in 2025 to a central estimate of 6.2 (95% range 0.00–14). A 5-year backtest shows a typical error of ±24.5%, with 100% of held-out values landing inside the 95% band.

-47%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 →
6.2Projected 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 →
0.00–1495% 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 →
±24.5%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, Brewer's Blackbird in Northern Rockies is projected to fall about 47% by 2030 — from 12 in 2025 to a central estimate of 6.2 (95% range 0.00–14). A 5-year backtest shows a typical error of ±24.5%, 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 →
20267.90.5215
20277.50.0915
20287.10.0015
20296.70.0014
20306.20.0014

Routes In Northern Rockies

Routes recording Brewer's Blackbird 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 →
NowoodWYOMING1522025
BridgeportOREGON1132025
Twin BridgesMONTANA1021976
St MaryMONTANA1002008
SpartaOREGON942025
DanielWYOMING511988
BoulderWYOMING512025
Crane CreekIDAHO482019
St. Mary 2MONTANA482025
CascadeIDAHO451984
Clover CreekOREGON432025
AugustaMONTANA422025
Freeman CreekMONTANA422016
Wolf CreekMONTANA412025
Fort LoganMONTANA412025
AlturasIDAHO381987
Malheur Res.OREGON382023
Green RiverWYOMING381984
GlenMONTANA372025
MeeteetseWYOMING372025
RaynesfordMONTANA342025
Patrick DrawWYOMING331980
LayCOLORADO322025
EllistonMONTANA312025
DiamondvilleWYOMING311982

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