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Species · Wisconsin · BBS 2026 Release · 1966–2025

Nashville Warbler Population Trend in Wisconsin

All statesForest birds

Nashville Warbler in Wisconsin has surged: up 77% on the route-weighted index since 1968.

+77%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 Nashville 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 →

Nashville Warbler has surged in Wisconsin: up 77% on the route-weighted index since 1968.

Nashville Warbler Population Forecast in Wisconsin

If the recent trend holds, Nashville Warbler in Wisconsin is projected to rise about 44% by 2030 — from 3.7 in 2025 to a central estimate of 5.3 (95% range 2.7–7.9). A 5-year backtest shows a typical error of ±57.7%, with 80% of held-out values landing inside the 95% band.

+44%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 →
5.3Projected 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 →
2.7–7.995% 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 →
±57.7%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, Nashville Warbler in Wisconsin is projected to rise about 44% by 2030 — from 3.7 in 2025 to a central estimate of 5.3 (95% range 2.7–7.9). A 5-year backtest shows a typical error of ±57.7%, with 80% 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 →
20265.12.67.7
20275.22.67.8
20285.22.67.8
20295.32.77.8
20305.32.77.9

Nashville Warbler Survey Routes in Wisconsin

Routes recording Nashville 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 →
Land O' Lakes 24220252017
Cavour2420251998
Eagle River2320251966
Popple River2220251967
Mcnaughton1920241968
Conover1920251998
Montreal1620251968
Mellen1520252002
Flambeau1520251998
Rhinelander1520231998
Land O Lakes1420161967
Amberg1420251980
Shanagolden1220251966
Chaffey1120251966
Iron River1120251967
Grand View1120251966
Bayfield920251967
Couderay920191969
Amnicon Falls920251998
Wausaukee820251980
Pigeon Creek520252008
Irma520251967
Loraine420181966
Minong320251967
Union Twp220241975

Nashville Warbler Population Trend in Other States

californiaconnecticutidahomainemarylandmassachusettsmichiganminnesotamontananew-hampshirenew-jerseynew-yorknorth-dakotaoregonpennsylvaniarhode-islandvermontvirginiawashingtonwest-virginia

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