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

Common Loon Population Trend in Wisconsin

All statesWetland birds

Common Loon in Wisconsin has edged up: up 20% on the route-weighted index since 1968.

+20%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 →
47Routes 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 →
58YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Common Loon 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 Common Loon in Wisconsin. See the full index history below.

Common Loon Population Forecast in Wisconsin

If the recent trend holds, Common Loon in Wisconsin is projected to rise about 51% by 2029 — from 0.43 in 2024 to a central estimate of 0.65 (95% range 0.29–1.0). A 5-year backtest shows a typical error of ±75.3%, with 80% of held-out values landing inside the 95% band.

+51%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 →
0.65Projected 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 →
0.29–1.095% 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 →
±75.3%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, Common Loon in Wisconsin is projected to rise about 51% by 2029 — from 0.43 in 2024 to a central estimate of 0.65 (95% range 0.29–1.0). A 5-year backtest shows a typical error of ±75.3%, with 80% of held-out values landing inside the 95% band.19662029
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 →
20250.640.281.00
20260.640.291.0
20270.650.291.0
20280.650.291.0
20290.650.291.0

Common Loon Survey Routes in Wisconsin

Routes recording Common Loon 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 →
Conover620241998
Loraine520181966
Land O' Lakes 2420242017
Grand View320241967
Land O Lakes320161967
Union Twp320231968
Weyerhauser320241969
Cadott320112011
Oconto Falls320231969
Flambeau320241999
Hudson220241997
Dresser220211966
Couderay220191969
Gilman220241987
Irma220231967
Mcnaughton220241966
Eagle River220241966
Popple River220241966
Crandon220241967
Hatfield219951995
Mather220131995
Elderon220212021
Rhinelander220221998
Chaffey120132000
Iron River120241971

Common Loon Population Trend in Other States

alaskaidahomainemassachusettsmichiganminnesotamontananew-hampshirenew-yorknorth-dakotaoregonvermontwashingtonwyoming

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