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Species · Wisconsin · BBS 2026 Release · 1966–2025

Mourning Warbler Population Trend in Wisconsin

All statesForest birds

Mourning Warbler in Wisconsin has increased: up 35% on the route-weighted index since 1968.

+35%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 →
80Routes 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 Mourning 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 →

No notable trend signals for Mourning Warbler in Wisconsin. See the full index history below.

Mourning Warbler Population Forecast in Wisconsin

If the recent trend holds, Mourning Warbler in Wisconsin is projected to rise about 43% by 2030 — from 2.0 in 2025 to a central estimate of 2.9 (95% range 1.1–4.7). A 5-year backtest shows a typical error of ±67%, with 100% of held-out values landing inside the 95% band.

+43%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 →
2.9Projected 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 →
1.1–4.795% 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 →
±67%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, Mourning Warbler in Wisconsin is projected to rise about 43% by 2030 — from 2.0 in 2025 to a central estimate of 2.9 (95% range 1.1–4.7). A 5-year backtest shows a typical error of ±67%, 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 →
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20302.91.14.7

Mourning Warbler Survey Routes in Wisconsin

Routes recording Mourning 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 →
Shanagolden1920251966
Mellen1520251998
Bayfield1320251967
Popple River1320251966
Cavour1320251998
Hollister1120251967
Grand View1020251966
Iron River720251967
Montreal720251968
Chaffey620251966
Land O Lakes620161967
Amberg620251980
Mcnaughton520241967
Land O' Lakes 2520252017
Amnicon Falls520251998
Conover520251998
Crandon420251967
Minong320241967
Hatfield319791978
Wis Rapids320151981
Stevens Pt320231980
Flambeau320251998
Gresham320251998
Couderay220251969
Exeland220251968

Mourning Warbler Population Trend in Other States

connecticutillinoisindianamainemarylandmassachusettsmichiganminnesotanew-hampshirenew-yorknorth-dakotaohiopennsylvaniavermontwest-virginia

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