BirdAnalyst
Species · Wisconsin · BBS 2025 Release · 1966–2024

Trumpeter Swan Population Trend in Wisconsin

All statesWaterfowl

Trumpeter Swan in Wisconsin has surged: up 675% on the route-weighted index since 1995.

+675%Since 1995TrendPercent 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 →
26Routes 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 →
22YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Trumpeter Swan 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 →

Trumpeter Swan has surged in Wisconsin: up 675% on the route-weighted index since 1995.

Trumpeter Swan Population Forecast in Wisconsin

If the recent trend holds, Trumpeter Swan in Wisconsin is projected to fall about 41% by 2029 — from 0.62 in 2024 to a central estimate of 0.36 (95% range 0.13–0.60). A 5-year backtest shows a typical error of ±315.8%, with 20% of held-out values landing inside the 95% band.

-41%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 →
0.36Projected 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 →
0.13–0.6095% 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 →
±315.8%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, Trumpeter Swan in Wisconsin is projected to fall about 41% by 2029 — from 0.62 in 2024 to a central estimate of 0.36 (95% range 0.13–0.60). A 5-year backtest shows a typical error of ±315.8%, with 20% of held-out values landing inside the 95% band.19932029
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 →
20250.320.080.55
20260.330.100.56
20270.340.100.57
20280.350.120.59
20290.360.130.60

Trumpeter Swan Survey Routes in Wisconsin

Routes recording Trumpeter Swan 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 →
Bashaw1520242021
Loraine1420211995
Hudson1320242007
Brownsville820222022
Dresser720242012
Cavour520222022
Mather420231994
Buena Vista420242024
Minong320032003
Gilman320242013
Flambeau320172013
Grand View220242014
Shanagolden220212009
Cumberland220242011
Weyerhauser220232023
Princeton220242024
N Andover220222022
Land O Lakes120142011
Union Twp120232007
Couderay120152015
Pigeon Creek120242022
Cochrane120222022
Unity120172017
Manawa119931993
Conover120232023

Trumpeter Swan Population Trend in Other States

alaskaarkansasidahoiowamichiganminnesotamontananebraskanevadanorth-dakotaohiooregonsouth-dakotautahwashingtonwyoming

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