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

Northern Parula Population Trend in Wisconsin

All statesForest birds

Northern Parula in Wisconsin has surged: up 142% on the route-weighted index since 1968.

+142%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 →
42Routes 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 Parula 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 Parula has surged in Wisconsin: up 142% on the route-weighted index since 1968.

Northern Parula Population Forecast in Wisconsin

If the recent trend holds, Northern Parula in Wisconsin is projected to rise about 25% by 2029 — from 0.47 in 2024 to a central estimate of 0.59 (95% range 0.38–0.80). A 5-year backtest shows a typical error of ±18.7%, with 100% of held-out values landing inside the 95% band.

+25%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 →
0.59Projected 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 →
0.38–0.8095% 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 →
±18.7%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 Parula in Wisconsin is projected to rise about 25% by 2029 — from 0.47 in 2024 to a central estimate of 0.59 (95% range 0.38–0.80). A 5-year backtest shows a typical error of ±18.7%, 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 →
20250.560.350.77
20260.570.360.78
20270.570.370.78
20280.580.370.79
20290.590.380.80

Northern Parula Survey Routes in Wisconsin

Routes recording Northern Parula 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 →
Land O Lakes920161967
Eagle River720241966
Land O' Lakes 2520242017
Popple River420241966
Cavour420241998
Conover320241998
Bayfield220241969
Shanagolden220241966
Couderay220151969
Rib Lake220241970
Crandon220241967
Weirgor Springs220092009
Flambeau220241999
Rhinelander220231998
Chaffey120111979
Iron River120241967
Minong120141971
Grand View120241967
Montreal120241968
Dresser120182018
Loraine120071984
Cumberland120162016
Weyerhauser119741974
Gilman120122012
Phillips120092009

Northern Parula Population Trend in Other States

alabamaarkansascaliforniaconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginia

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