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Species · Illinois · BBS 2025 Release · 1966–2024

Hooded Warbler Population Trend in Illinois

All statesForest birds

Hooded Warbler in Illinois has increased: up 34% on the route-weighted index since 1981.

+34%Since 1981TrendPercent 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 →
9Routes 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 →
31YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Hooded Warbler Trends in IllinoisNotable 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 Hooded Warbler in Illinois. See the full index history below.

Hooded Warbler Population Forecast in Illinois

If the recent trend holds, Hooded Warbler in Illinois is projected to stay roughly flat through 2029, near 0.03 (95% range 0.00–0.06). A 5-year backtest shows a typical error of ±44%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.03Projected 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 →
0.00–0.0695% 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 →
±44%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, Hooded Warbler in Illinois is projected to stay roughly flat through 2029, near 0.03 (95% range 0.00–0.06). A 5-year backtest shows a typical error of ±44%, with 100% of held-out values landing inside the 95% band.19712029
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 →
20250.030.000.06
20260.030.000.06
20270.030.000.06
20280.030.000.06
20290.030.000.06

Hooded Warbler Survey Routes in Illinois

Routes recording Hooded Warbler in Illinois.
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 →
Sandusky220222000
Dailey120052005
Concord120111981
Itasca119921992
Sheffield120052005
Wayne120212021
Cave In Rock120241995
Jamestown119711971
Delwood120231980

Hooded Warbler Population Trend in Other States

alabamaarkansasconnecticutdelawarefloridageorgiaindianakentuckylouisianamarylandmassachusettsmichiganmississippimissourinew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvirginiawest-virginiawisconsin

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