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

Chestnut-sided Warbler Population Trend in Wisconsin

All statesForest birds

Chestnut-sided Warbler in Wisconsin has surged: up 114% on the route-weighted index since 1968.

+114%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 →
87Routes 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 Chestnut-sided Warbler 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 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 →

Chestnut-sided Warbler has surged in Wisconsin: up 114% on the route-weighted index since 1968.

Chestnut-sided Warbler Population Forecast in Wisconsin

If the recent trend holds, Chestnut-sided Warbler in Wisconsin is projected to rise about 22% by 2029 — from 7.3 in 2024 to a central estimate of 8.9 (95% range 6.7–11). A 5-year backtest shows a typical error of ±10.4%, with 100% of held-out values landing inside the 95% band.

+22%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 →
8.9Projected 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 →
6.7–1195% 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 →
±10.4%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, Chestnut-sided Warbler in Wisconsin is projected to rise about 22% by 2029 — from 7.3 in 2024 to a central estimate of 8.9 (95% range 6.7–11). A 5-year backtest shows a typical error of ±10.4%, 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 →
20258.76.511
20268.76.511
20278.86.611
20288.96.711
20298.96.711

Chestnut-sided Warbler Survey Routes in Wisconsin

Routes recording Chestnut-sided Warbler 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 →
Weirgor Springs3520241999
Grand View3420241966
Conover3320241998
Union Twp3220241975
Mcnaughton3220241966
Minong3120241967
Mellen2920241998
Irma2820241967
Couderay2620191969
Iron River2520241967
Shanagolden2520241966
Popple River2420241966
Amberg2420241980
Bayfield2020241967
Wausaukee1720241980
Land O' Lakes 21720242017
Montreal1520241968
Rib Lake1520241966
Amnicon Falls1520241998
Flambeau1520241998
Chaffey1420241966
Gilman1420241966
Hollister1220241967
Cumberland1120241966
Stevens Pt1120231966

Chestnut-sided Warbler Population Trend in Other States

alabamaarkansascoloradoconnecticutgeorgiaillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotanevadanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiopennsylvaniarhode-islandtennesseevermontvirginiawest-virginiawyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.