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Species · Wisconsin · BBS 2026 Release · 1966–2025

Black-throated Green Warbler Population Trend in Wisconsin

All statesForest birds

Black-throated Green Warbler in Wisconsin has surged: up 80% on the route-weighted index since 1968.

+80%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 →
45Routes 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 Black-throated Green 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 →

Black-throated Green Warbler has surged in Wisconsin: up 80% on the route-weighted index since 1968.

Black-throated Green Warbler Population Forecast in Wisconsin

If the recent trend holds, Black-throated Green Warbler in Wisconsin is projected to rise about 48% by 2030 — from 2.0 in 2025 to a central estimate of 3.0 (95% range 2.0–4.0). A 5-year backtest shows a typical error of ±32.7%, with 80% of held-out values landing inside the 95% band.

+48%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 →
3.0Projected 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 →
2.0–4.095% 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 →
±32.7%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, Black-throated Green Warbler in Wisconsin is projected to rise about 48% by 2030 — from 2.0 in 2025 to a central estimate of 3.0 (95% range 2.0–4.0). A 5-year backtest shows a typical error of ±32.7%, 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 →
20262.91.93.9
20272.91.93.9
20283.01.94.0
20293.02.04.0
20303.02.04.0

Black-throated Green Warbler Survey Routes in Wisconsin

Routes recording Black-throated Green 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 →
Washington I4120251967
Land O Lakes2420161967
Eagle River1820251966
Mellen1520251998
Mcnaughton1220241970
Land O' Lakes 21220252017
Shanagolden1020251966
Cavour1020251998
Conover920251998
Chaffey720251967
Popple River720251966
Grand View520251966
Rhinelander520231998
Crandon420251967
Wausaukee420251980
Flambeau420251998
Montreal320251968
Stevens Pt320231983
Gresham320241998
Iron River220251967
Bayfield220251967
Couderay220191973
Rib Lake220251966
Hollister220251967
Amberg220251980

Black-throated Green Warbler Population Trend in Other States

alabamaarkansasconnecticutgeorgiaindianakentuckymainemarylandmassachusettsmichiganminnesotamissourinew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseevermontvirginiawest-virginia

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