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Species · Wisconsin · BBS 2025 Release · 1966–2024

Black-throated Blue Warbler Population Trend in Wisconsin

All statesForest birds

Black-throated Blue Warbler in Wisconsin has surged: up 502% on the route-weighted index since 1975.

+502%Since 1975TrendPercent 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 →
21Routes 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 →
46YearsYears 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 Blue 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 Blue Warbler has surged in Wisconsin: up 502% on the route-weighted index since 1975.

Black-throated Blue Warbler Population Forecast in Wisconsin

If the recent trend holds, Black-throated Blue Warbler in Wisconsin is projected to rise about 100% by 2029 — from 0.06 in 2024 to a central estimate of 0.12 (95% range 0.05–0.20). A 5-year backtest shows a typical error of ±40.7%, with 80% of held-out values landing inside the 95% band.

+100%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 →
0.12Projected 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 →
0.05–0.2095% 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 →
±40.7%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 Blue Warbler in Wisconsin is projected to rise about 100% by 2029 — from 0.06 in 2024 to a central estimate of 0.12 (95% range 0.05–0.20). A 5-year backtest shows a typical error of ±40.7%, with 80% of held-out values landing inside the 95% band.19732029
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 →
20250.120.040.19
20260.120.040.19
20270.120.050.19
20280.120.050.20
20290.120.050.20

Black-throated Blue Warbler Survey Routes in Wisconsin

Routes recording Black-throated Blue 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 →
Minong219951995
Montreal220231980
Crandon220132012
Flambeau220132013
Land O' Lakes 2220222017
Grand View120232002
Bayfield120241999
Shanagolden120221980
Land O Lakes120161980
Gilman119881988
Mcnaughton120162002
Eagle River120231973
Popple River120241981
Hollister120171990
Amberg120162016
Washington I119971997
Oconto Falls119971997
Mellen120242003
Conover120241998
Weirgor Springs120162016
Cavour120241999

Black-throated Blue Warbler Population Trend in Other States

connecticutgeorgiamainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinapennsylvaniarhode-islandtennesseevermontvirginiawest-virginia

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