BirdAnalyst
Species · Indiana · BBS 2026 Release · 1966–2025

Vesper Sparrow Population Trend in Indiana

All statesGrassland birds

Vesper Sparrow in Indiana has collapsed: down 90% on the route-weighted index since 1968.

-90%Since 1968TrendPercent 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 →
58Routes 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 →
59YearsYears 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 IndianaNotable 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 →

Vesper Sparrow has collapsed in Indiana: down 90% on the route-weighted index since 1968.

Vesper Sparrow Population Forecast in Indiana

If the recent trend holds, Vesper Sparrow in Indiana is projected to fall about 32% by 2030 — from 1.5 in 2025 to a central estimate of 1.0 (95% range 0.00–5.0). A 5-year backtest shows a typical error of ±65.9%, with 100% of held-out values landing inside the 95% band.

-32%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 →
1.0Projected 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 →
0.00–5.095% 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 →
±65.9%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 Indiana is projected to fall about 32% by 2030 — from 1.5 in 2025 to a central estimate of 1.0 (95% range 0.00–5.0). A 5-year backtest shows a typical error of ±65.9%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20261.70.005.6
20271.50.005.4
20281.30.005.3
20291.20.005.1
20301.00.005.0

Vesper Sparrow Survey Routes in Indiana

Routes recording Vesper Sparrow in Indiana.
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 →
Kewanna2220221981
Sexton1820161983
W Lafayette1420251981
Packertown1119931967
Jamestown1020251986
Monticello820251981
Tipton819921966
Maplewood820212017
Laporte820231999
Anderson620252000
Thorntown520251982
Rensselaer420251999
Frankfort420221999
Decatur420252002
Spencer320211970
Montpelier320242018
Portage320002000
Lakeville320242011
Knox220251981
Columbia Cty220241981
Fowler220251966
Galveston220251981
Cumback220041966
Evansville219841968
New Brunswick220252024

Vesper Sparrow Population Trend in Other States

arizonacaliforniacoloradoconnecticutdelawareidahoillinoisiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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