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

Brewer's Blackbird Population Trend in Oregon

All statesGeneralists

Brewer's Blackbird in Oregon has fallen sharply: down 56% on the route-weighted index since 1970.

-56%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 →
129Routes 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 OregonNotable 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 Oregon: down 56% on the route-weighted index since 1970.

Brewer's Blackbird Population Forecast in Oregon

If the recent trend holds, Brewer's Blackbird in Oregon is projected to fall about 41% by 2029 — from 16 in 2024 to a central estimate of 9.7 (95% range 0.00–23). A 5-year backtest shows a typical error of ±38.5%, 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 →
9.7Projected 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 →
0.00–2395% 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 →
±38.5%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 Oregon is projected to fall about 41% by 2029 — from 16 in 2024 to a central estimate of 9.7 (95% range 0.00–23). A 5-year backtest shows a typical error of ±38.5%, 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 →
2025120.0026
2026120.0025
2027110.0024
2028100.0024
20299.70.0023

Brewer's Blackbird Survey Routes in Oregon

Routes recording Brewer's Blackbird in Oregon.
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 →
Umatilla30320231988
Modoc Point 217720242024
Joseph15220241971
Princeton14219851972
Modoc Point13420181969
Malheur Nwr12120221986
Emigrant Lk10220011972
Fandango Can9720241977
Catlow Rim7520241993
Sparta7320011971
Trout Creek6520211996
Bly5920011973
Crane5920241993
Zumwalt5920051995
Warner Vally5620241993
Pendleton4620241972
Bly 24120242007
Green Mtn.4020241994
Malheur Res.3820232022
Sandy River3620061993
Flook Lake3320241994
Elkton3220241972
Canby3220241993
Salem3220241993
Deschutes3120241968

Brewer's Blackbird Population Trend in Other States

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