BirdAnalyst
Species · South Dakota · BBS 2026 Release · 1966–2025

Brewer's Blackbird Population Trend in South Dakota

All statesGeneralists

Brewer's Blackbird in South Dakota has surged: up 351% on the route-weighted index since 1969.

+351%Since 1969TrendPercent 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 →
46Routes 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 →
58YearsYears 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 South DakotaNotable 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 increasecomputed 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 surged in South Dakota: up 350% on the route-weighted index since 1969.

Brewer's Blackbird Population Forecast in South Dakota

If the recent trend holds, Brewer's Blackbird in South Dakota is projected to stay roughly flat through 2030, near 3.3 (95% range 1.3–5.4). A 5-year backtest shows a typical error of ±33%, with 100% of held-out values landing inside the 95% band.

-4%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 →
1.3–5.495% 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 →
±33%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 South Dakota is projected to stay roughly flat through 2030, near 3.3 (95% range 1.3–5.4). A 5-year backtest shows a typical error of ±33%, with 100% of held-out values landing inside the 95% band.19672030
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 →
20263.21.25.2
20273.21.25.3
20283.31.25.3
20293.31.35.3
20303.31.35.4

Brewer's Blackbird Survey Routes in South Dakota

Routes recording Brewer's Blackbird in South Dakota.
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 →
Reva2520251979
Wind Cave Np2320251999
Roubaix Lk1919911967
Harding1920251968
Custer1720251967
Ft Thompson1620041999
Forbes1520241967
Englewood1320111992
Cedar Pass1119801967
Ardmore820192011
Marcus720151999
Hazelrodt720251992
Indian420181999
Broadland420132012
Wilmot420132013
Maurine420241968
Lodgepole420252011
Isabel420112011
White River420122011
Rochford420181996
Lane 2420142013
French Creek320051995
Long Lake320142012
Hayes320231999
Black Fox319951992

Brewer's Blackbird Population Trend in Other States

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