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Species · Wisconsin · BBS 2026 Release · 1966–2025

Northern Waterthrush Population Trend in Wisconsin

All statesForest birds

Northern Waterthrush in Wisconsin has surged: up 503% on the route-weighted index since 1968.

+503%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 →
52Routes 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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Northern Waterthrush 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 →

Northern Waterthrush has surged in Wisconsin: up 503% on the route-weighted index since 1968.

Northern Waterthrush Population Forecast in Wisconsin

If the recent trend holds, Northern Waterthrush in Wisconsin is projected to fall about 29% by 2030 — from 0.46 in 2025 to a central estimate of 0.32 (95% range 0.13–0.51). A 5-year backtest shows a typical error of ±25%, with 100% of held-out values landing inside the 95% band.

-29%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 →
0.32Projected 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 →
0.13–0.5195% 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 →
±25%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, Northern Waterthrush in Wisconsin is projected to fall about 29% by 2030 — from 0.46 in 2025 to a central estimate of 0.32 (95% range 0.13–0.51). A 5-year backtest shows a typical error of ±25%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20260.310.120.50
20270.320.120.51
20280.320.130.51
20290.320.130.51
20300.320.130.51

Northern Waterthrush Survey Routes in Wisconsin

Routes recording Northern Waterthrush 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 →
Rib Lake520251966
Casco420251967
Cavour420251998
Gresham420251998
Grimms420211999
Chaffey320131976
Amberg320251980
Wausaukee320251980
Unity319741974
Shanagolden220251969
Holway219761968
Merrill220251966
Irma220231984
Stetsonville220251992
Iron River120221986
Grand View120111972
Bayfield120211977
Montreal120251969
Land O Lakes120022002
Dresser120102010
Loraine120152006
Cumberland120122005
Weyerhauser120151985
Couderay120111992
Exeland120242001

Northern Waterthrush Population Trend in Other States

alaskaconnecticutidahomainemarylandmassachusettsmichiganminnesotamontananew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiopennsylvaniarhode-islandvermontvirginiawashingtonwest-virginiawyoming

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