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

Vesper Sparrow Population Trend in South Dakota

All statesGrassland birds

Vesper Sparrow in South Dakota has declined: down 29% on the route-weighted index since 1969.

-29%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 →
62Routes 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 Vesper Sparrow 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 →

No notable trend signals for Vesper Sparrow in South Dakota. See the full index history below.

Vesper Sparrow Population Forecast in South Dakota

If the recent trend holds, Vesper Sparrow in South Dakota is projected to rise about 70% by 2030 — from 3.1 in 2025 to a central estimate of 5.2 (95% range 1.9–8.5). A 5-year backtest shows a typical error of ±78.7%, 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 →
5.2Projected 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 →
1.9–8.595% 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 →
±78.7%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, Vesper Sparrow in South Dakota is projected to rise about 70% by 2030 — from 3.1 in 2025 to a central estimate of 5.2 (95% range 1.9–8.5). A 5-year backtest shows a typical error of ±78.7%, 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 →
20265.22.08.5
20275.22.08.5
20285.21.98.5
20295.21.98.5
20305.21.98.5

Vesper Sparrow Survey Routes in South Dakota

Routes recording Vesper Sparrow 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 →
Eagle Butte6220152010
Isabel4120152009
Promise3620151972
Pleasant Val1520241992
Harding1420251967
Raymond1320211967
Gettysburg1320231969
Howard1120251970
Wilmot1020251967
Veblen1020231967
Roswell920101968
Britton920231970
Wind Cave Np920251999
Lane819991985
Volga720251967
Forbes720251977
Volunteer720251967
Hill City720131992
Elk Mountain720041992
Tripp520251967
Rosebud520071967
Silver City420021992
Rockyford320252003
Lodgepole320251990
Ardmore320152013

Vesper Sparrow Population Trend in Other States

arizonacaliforniacoloradoconnecticutdelawareidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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