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

Northern Waterthrush Population Trend in Wisconsin

All statesForest birds

Northern Waterthrush in Wisconsin has surged: up 382% on the route-weighted index since 1968.

+382%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 →
51Routes 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 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 382% 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 rise about 13% by 2029 — from 0.27 in 2024 to a central estimate of 0.31 (95% range 0.12–0.50). A 5-year backtest shows a typical error of ±21.3%, with 100% of held-out values landing inside the 95% band.

+13%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 →
0.31Projected 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 →
0.12–0.5095% 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 →
±21.3%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, Northern Waterthrush in Wisconsin is projected to rise about 13% by 2029 — from 0.27 in 2024 to a central estimate of 0.31 (95% range 0.12–0.50). A 5-year backtest shows a typical error of ±21.3%, with 100% 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 →
20250.300.110.49
20260.300.110.49
20270.300.120.49
20280.310.120.49
20290.310.120.50

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 →
Cavour420231998
Grimms420211999
Chaffey320131976
Montreal320241969
Merrill320241966
Wausaukee320231980
Unity319741974
Flambeau320242000
Holway219761968
Rib Lake220241966
Irma220231984
Amberg220241980
Casco220231967
Gresham220241998
Iron River120221986
Grand View120111972
Bayfield120211977
Shanagolden120241969
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 2026-05-22.