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

Ovenbird Population Trend in Illinois

All statesForest birds

Ovenbird in Illinois has declined: down 41% on the route-weighted index since 1969.

-41%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 →
30Routes 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 →
54YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Ovenbird 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 Ovenbird in Illinois. See the full index history below.

Ovenbird Population Forecast in Illinois

If the recent trend holds, Ovenbird in Illinois is projected to stay roughly flat through 2029, near 0.05 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±39.5%, 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 →
0.05Projected 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 →
0.00–0.1295% 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 →
±39.5%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, Ovenbird in Illinois is projected to stay roughly flat through 2029, near 0.05 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±39.5%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.050.000.12
20260.050.000.12
20270.050.000.12
20280.050.000.12
20290.050.000.12

Ovenbird Survey Routes in Illinois

Routes recording Ovenbird 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 →
Belleview520161982
Holcomb419781978
Cave In Rock420231995
Guilford120031974
Barrington119971997
Itasca120021985
Geneseo119941970
Sheffield119911990
Compton119801980
Wayne120121974
New Lenox119721969
Terre Haute119901990
Bartonville120152000
Monica120012001
Pontiac119881988
Clarksdale119691969
Humboldt119931993
Mascoutah Lk119911989
Jamestown119731967
Eubanks120242002
Marshall120102010
Bremen120142008
Belknap120022002
Delwood120241971
Beaverdam Lk120021990

Ovenbird Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawaregeorgiaindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseeutahvermontvirginiawest-virginiawisconsinwyoming

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