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Species · South Dakota · BBS 2025 Release · 1966–2024

Brewer's Blackbird Population Trend in South Dakota

All statesGeneralists

Brewer's Blackbird in South Dakota has surged: up 308% on the route-weighted index since 1969.

+308%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 →
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 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 308% 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 fall about 19% by 2029 — from 4.0 in 2024 to a central estimate of 3.3 (95% range 1.2–5.3). A 5-year backtest shows a typical error of ±32.7%, with 100% of held-out values landing inside the 95% band.

-19%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 →
3.3Projected 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 →
1.2–5.395% 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 →
±32.7%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 fall about 19% by 2029 — from 4.0 in 2024 to a central estimate of 3.3 (95% range 1.2–5.3). A 5-year backtest shows a typical error of ±32.7%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20253.21.15.2
20263.21.25.2
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20283.31.25.3
20293.31.25.3

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 →
Wind Cave Np2920241999
Reva2420241979
Roubaix Lk1919911967
Ft Thompson1620041999
Forbes1520241967
Custer1520241967
Englewood1320111992
Cedar Pass1119801967
Harding1020191968
Ardmore820192011
Marcus720151999
Lightning Cr620221992
Indian420181999
Broadland420132012
Wilmot420132013
Maurine420241968
Isabel420112011
White River420122011
Rochford420181996
Lane 2420142013
French Creek320051995
Long Lake320142012
Lodgepole320222011
Hayes320231999
Black Fox319951992

Brewer's Blackbird Population Trend in Other States

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