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

MacGillivray's Warbler Population Trend in South Dakota

All statesForest birds

MacGillivray's Warbler in South Dakota has surged: up 109% on the route-weighted index since 1993.

+109%Since 1993TrendPercent 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 →
10Routes 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 →
31YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable MacGillivray's Warbler 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 →

MacGillivray's Warbler has surged in South Dakota: up 109% on the route-weighted index since 1993.

MacGillivray's Warbler Population Forecast in South Dakota

If the recent trend holds, MacGillivray's Warbler in South Dakota is projected to fall about 70% by 2030 — from 0.29 in 2025 to a central estimate of 0.09 (95% range 0.00–0.32). A 5-year backtest shows a typical error of ±73%, with 100% of held-out values landing inside the 95% band.

-70%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 →
0.09Projected 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 →
0.00–0.3295% 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 →
±73%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, MacGillivray's Warbler in South Dakota is projected to fall about 70% by 2030 — from 0.29 in 2025 to a central estimate of 0.09 (95% range 0.00–0.32). A 5-year backtest shows a typical error of ±73%, with 100% of held-out values landing inside the 95% band.19812030
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 →
20260.090.000.33
20270.090.000.33
20280.090.000.33
20290.090.000.32
20300.090.000.32

MacGillivray's Warbler Survey Routes in South Dakota

Routes recording MacGillivray's Warbler 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 →
Rochford520251996
Long Draw320251994
Englewood220211994
Norbeck220001993
Hazelrodt120011993
Lightning Cr120091992
Hill City120131996
Black Fox120171994
Roubaix Lk119811981
Silver City120021992

MacGillivray's Warbler Population Trend in Other States

alaskaarizonacaliforniacoloradoidahomontananevadanew-mexicooregontexasutahwashingtonwyoming

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