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

Chestnut-sided Warbler Population Trend in Wisconsin

All statesForest birds

Chestnut-sided Warbler in Wisconsin has surged: up 112% on the route-weighted index since 1968.

+112%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 →
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 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 112% 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 stay roughly flat through 2030, near 8.9 (95% range 6.7–11). A 5-year backtest shows a typical error of ±11.9%, with 100% of held-out values landing inside the 95% band.

+10%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 →
8.9Projected 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 →
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 →
±11.9%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, Chestnut-sided Warbler in Wisconsin is projected to stay roughly flat through 2030, near 8.9 (95% range 6.7–11). A 5-year backtest shows a typical error of ±11.9%, 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 →
20268.76.511
20278.86.611
20288.86.611
20298.96.711
20308.96.711

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 →
Minong3820251967
Amberg3820251980
Land O' Lakes 23620252017
Bayfield3320251967
Mcnaughton3220241966
Mellen3220251998
Shanagolden3120251966
Grand View2620251966
Popple River2420251966
Amnicon Falls2420251998
Flambeau2420251998
Rib Lake2220251966
Hollister2220251967
Bashaw2120251998
Conover2020251998
Weirgor Springs2020251999
Cumberland1920251966
Iron River1720251967
Montreal1720251968
Exeland1620251968
Irma1620251967
Cavour1620251998
Union Twp1520251975
Chaffey1420251966
Couderay1320251969

Chestnut-sided Warbler Population Trend in Other States

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

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