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

Magnolia Warbler Population Trend in Wisconsin

All statesForest birds

Magnolia Warbler in Wisconsin has surged: up 400% on the route-weighted index since 1969.

+400%Since 1969TrendPercent 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 →
35Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Magnolia Warbler 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 →

Magnolia Warbler has surged in Wisconsin: up 400% on the route-weighted index since 1969.

Magnolia Warbler Population Forecast in Wisconsin

If the recent trend holds, Magnolia Warbler in Wisconsin is projected to rise about 41% by 2029 — from 0.38 in 2024 to a central estimate of 0.54 (95% range 0.32–0.76). A 5-year backtest shows a typical error of ±24.1%, with 100% 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 →
0.54Projected 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 →
0.32–0.7695% 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 →
±24.1%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, Magnolia Warbler in Wisconsin is projected to rise about 41% by 2029 — from 0.38 in 2024 to a central estimate of 0.54 (95% range 0.32–0.76). A 5-year backtest shows a typical error of ±24.1%, 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 →
20250.510.300.73
20260.520.300.74
20270.530.310.74
20280.530.320.75
20290.540.320.76

Magnolia Warbler Survey Routes in Wisconsin

Routes recording Magnolia Warbler 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' Lakes 21020242017
Land O Lakes820161970
Eagle River720241966
Irma320231969
Hollister320161997
Rhinelander320232000
Cavour320241998
Shanagolden220241969
Montreal220241968
Mcnaughton220241970
Wausaukee220181981
Mather220002000
Chaffey120211970
Iron River120241971
Minong120131971
Grand View120241972
Bayfield120211973
Pigeon Creek120212015
Loraine120181982
Cumberland120182017
Couderay120181987
Phillips120081985
Rib Lake120131971
Merrill119981989
Popple River120241968

Magnolia Warbler Population Trend in Other States

connecticutmainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinaohiopennsylvaniavermontvirginiawest-virginia

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