BirdAnalyst
Species · Wisconsin · BBS 2025 Release · 1966–2024

Savannah Sparrow Population Trend in Wisconsin

All statesGrassland birds

Savannah Sparrow in Wisconsin has collapsed: down 83% on the route-weighted index since 1968.

-83%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 →
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 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 83% 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 rise about 23% by 2029 — from 5.0 in 2024 to a central estimate of 6.2 (95% range 0.00–16). A 5-year backtest shows a typical error of ±106.6%, with 100% of held-out values landing inside the 95% band.

+23%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 →
6.2Projected 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 →
0.00–1695% 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 →
±106.6%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 rise about 23% by 2029 — from 5.0 in 2024 to a central estimate of 6.2 (95% range 0.00–16). A 5-year backtest shows a typical error of ±106.6%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20257.90.0017
20267.50.0017
20277.00.0016
20286.60.0016
20296.20.0016

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 River3420241967
Amnicon Falls3420241998
Grimms3220211998
Casco2920241966
Raymond2920241966
Bayfield2720241967
Omro1820011966
Kiel1820221998
Viroqua1720241966
Stratford1520241966
Paris1420241966
Colby1320241998
Cumberland1120241966
Weyerhauser1120241966
Annaton1120241998
Cadott1020241966
Merrill920241966
Wis Rapids920231966
Rolling Grnd920241966
Kendall920231967
Wiota920241966
Gilman820241966
Eden820241966
River Falls820241998

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 2026-05-22.