BirdAnalyst
Species · Wisconsin · BBS 2026 Release · 1966–2025

Bald Eagle Population Trend in Wisconsin

All statesBirds of prey

Bald Eagle in Wisconsin has surged: up 18× on the route-weighted index since 1979.

18×Since 1979TrendPercent 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 →
89Routes 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 →
47YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Bald Eagle 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 Bald Eagle in Wisconsin. See the full index history below.

Bald Eagle Population Forecast in Wisconsin

If the recent trend holds, Bald Eagle in Wisconsin is projected to fall about 13% by 2030 — from 0.57 in 2025 to a central estimate of 0.50 (95% range 0.35–0.64). A 5-year backtest shows a typical error of ±29.8%, with 40% of held-out values landing inside the 95% band.

-13%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 →
0.50Projected 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 →
0.35–0.6495% 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 →
±29.8%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, Bald Eagle in Wisconsin is projected to fall about 13% by 2030 — from 0.57 in 2025 to a central estimate of 0.50 (95% range 0.35–0.64). A 5-year backtest shows a typical error of ±29.8%, with 40% of held-out values landing inside the 95% band.19752030
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 →
20260.460.310.60
20270.470.320.61
20280.480.330.62
20290.490.340.63
20300.500.350.64

Bald Eagle Survey Routes in Wisconsin

Routes recording Bald Eagle 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 →
Exeland520251997
Weyerhauser420251996
Omro419961996
Merrill320241992
Irma320251994
Trempealeau320252003
Mather320231998
Casco320242005
Eden320252022
Rhinelander320211999
Gresham320252013
Dresser220251992
Loraine220181984
Gilman220241996
Wausaukee220132013
Cochrane220251989
Wis Rapids220231983
Clintonville220252001
New Lisbon220242010
Kendall220232007
Land O' Lakes 2220252025
Pigeon Creek220242012
Buena Vista220222014
Briggsville220192006
Chaffey120252025

Bald Eagle Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawyoming

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