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

Osprey Population Trend in Wisconsin

All statesBirds of prey

Osprey in Wisconsin has surged: up 538% on the route-weighted index since 1969.

+538%Since 1969TrendPercent 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 →
56Routes 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 →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Osprey 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 Osprey in Wisconsin. See the full index history below.

Osprey Population Forecast in Wisconsin

If the recent trend holds, Osprey in Wisconsin is projected to fall about 36% by 2030 — from 0.30 in 2025 to a central estimate of 0.19 (95% range 0.10–0.28). A 5-year backtest shows a typical error of ±35.2%, with 80% of held-out values landing inside the 95% band.

-36%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 →
0.19Projected 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 →
0.10–0.2895% 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 →
±35.2%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, Osprey in Wisconsin is projected to fall about 36% by 2030 — from 0.30 in 2025 to a central estimate of 0.19 (95% range 0.10–0.28). A 5-year backtest shows a typical error of ±35.2%, with 80% of held-out values landing inside the 95% band.19672030
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 →
20260.180.090.27
20270.180.100.28
20280.190.100.28
20290.190.100.28
20300.190.100.28

Osprey Survey Routes in Wisconsin

Routes recording Osprey 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 →
Omro 2820252002
Flambeau420251998
Gilman319921992
Couderay220191977
Omro220011997
Manitowoc220242007
Fall River220252024
Beaver Dam220132011
Minong120211979
Grand View120062006
Bayfield120001999
Shanagolden120161983
Montreal120192007
Land O Lakes120161988
Hudson120232007
Dresser120221990
Union Twp120101984
Loraine120181969
Cumberland120251989
Weyerhauser120241973
Exeland120112011
Phillips120252009
Rib Lake120251988
Merrill119761976
Irma120251968

Osprey Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawyoming

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