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

Savannah Sparrow Population Trend in Wisconsin

All statesGrassland birds

Savannah Sparrow in Wisconsin has collapsed: down 82% on the route-weighted index since 1968.

-82%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 →
93Routes 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 Savannah Sparrow Trends in WisconsinNotable 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 →

Savannah Sparrow has collapsed in Wisconsin: down 82% on the route-weighted index since 1968.

Savannah Sparrow Population Forecast in Wisconsin

If the recent trend holds, Savannah Sparrow in Wisconsin is projected to stay roughly flat through 2030, near 5.6 (95% range 0.00–15). A 5-year backtest shows a typical error of ±97.9%, with 100% of held-out values landing inside the 95% band.

-2%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 →
5.6Projected 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 →
0.00–1595% 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 →
±97.9%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, Savannah Sparrow in Wisconsin is projected to stay roughly flat through 2030, near 5.6 (95% range 0.00–15). A 5-year backtest shows a typical error of ±97.9%, 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 →
20267.30.0017
20276.90.0016
20286.40.0016
20296.00.0015
20305.60.0015

Savannah Sparrow Survey Routes in Wisconsin

Routes recording Savannah Sparrow in Wisconsin.
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 →
Holway6319891967
Iron River3720251967
Bayfield3420251967
Casco3320251966
Stetsonville3220251990
Grimms3220211998
Amnicon Falls2720251998
Raymond2320251966
Omro1820011966
Viroqua1720241966
Colby1720251998
Stratford1620251966
Holland1620251998
Kiel1420251998
Kendall1320251967
Chaffey1220251966
Gilmanton1220251966
Rolling Grnd1220251966
Paris1220251966
River Falls1120251998
New Lisbon1020251967
Annaton1020251998
Wis Rapids920231966
Merrill820251966
Trempealeau820251966

Savannah Sparrow Population Trend in Other States

alaskaarizonacaliforniacoloradoconnecticutdelawareidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawyoming

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