BirdAnalyst
Species · Idaho · BBS 2025 Release · 1966–2024

Brewer's Blackbird Population Trend in Idaho

All statesGeneralists

Brewer's Blackbird in Idaho has collapsed: down 80% on the route-weighted index since 1970.

-80%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 →
57Routes In StateSurvey 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 Brewer's Blackbird Trends in IdahoNotable 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 Idaho: down 80% on the route-weighted index since 1970.

Brewer's Blackbird Population Forecast in Idaho

If the recent trend holds, Brewer's Blackbird in Idaho is projected to fall about 100% by 2029 — from 11 in 2024 to a central estimate of 0.00 (95% range 0.00–27). A 5-year backtest shows a typical error of ±127.9%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–2795% 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 →
±127.9%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 Idaho is projected to fall about 100% by 2029 — from 11 in 2024 to a central estimate of 0.00 (95% range 0.00–27). A 5-year backtest shows a typical error of ±127.9%, 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 →
20250.000.0027
20260.000.0027
20270.000.0027
20280.000.0027
20290.000.0027

Brewer's Blackbird Survey Routes in Idaho

Routes recording Brewer's Blackbird in Idaho.
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 →
Glenns Ferry8419861968
Picabo5620211988
Bates5220231988
Crane Creek4820191988
Cascade4519841968
Dougal Res4120241988
Alturas3819871968
Henry3819831973
Baker3420241974
Blacks Creek3420171968
Leadore3320241974
Acequia2920061979
Iron Springs2820241988
Triangle2720241985
Daniels Res2620191988
Springfield2520181969
Joel2520241989
Sawtooth City 22020242015
Cedar Hill1920241989
Gifford1820171971
Almo1720231988
Sawtooth Cty1520141988
Pocatello1420191979
Nezperce Nf1419991992
Craters1320181979

Brewer's Blackbird Population Trend in Other States

arizonacaliforniacoloradoindianamichiganminnesotamontananebraskanevadanew-mexiconorth-dakotaoklahomaoregonsouth-dakotatexasutahwashingtonwisconsinwyoming

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