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Species · Wisconsin · BBS 2025 Release · 1966–2024

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 →
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 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 49% by 2029 — from 2.0 in 2024 to a central estimate of 3.0 (95% range 1.2–4.7). A 5-year backtest shows a typical error of ±62.4%, with 100% of held-out values landing inside the 95% band.

+49%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 →
3.0Projected 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 →
1.2–4.795% 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 →
±62.4%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, Mourning Warbler in Wisconsin is projected to rise about 49% by 2029 — from 2.0 in 2024 to a central estimate of 3.0 (95% range 1.2–4.7). A 5-year backtest shows a typical error of ±62.4%, 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 →
20252.91.24.7
20262.91.24.7
20272.91.24.7
20283.01.24.7
20293.01.24.7

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 →
Bayfield1520241967
Mellen1520241998
Montreal1320241968
Popple River1220241966
Cavour1020241998
Amnicon Falls920241998
Hollister820241967
Shanagolden720241966
Iron River620241967
Grand View620241966
Land O Lakes620161967
Amberg620241980
Land O' Lakes 2620242017
Chaffey520241966
Couderay520191969
Irma520241967
Mcnaughton520241967
Flambeau420241998
Minong320241967
Cumberland320181966
Cadott320191968
Hatfield319791978
Wis Rapids320151981
Stevens Pt320231980
Holway219891967

Mourning Warbler Population Trend in Other States

connecticutillinoisindianamainemarylandmassachusettsmichiganminnesotanew-hampshirenew-yorknorth-dakotaohiopennsylvaniavermontwest-virginia

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