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Species · Illinois · BBS 2025 Release · 1966–2024

Baltimore Oriole Population Trend in Illinois

All statesGeneralists

Baltimore Oriole in Illinois has held roughly steady: down 5% on the route-weighted index since 1968.

-5%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 →
105Routes 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 Baltimore Oriole 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 Baltimore Oriole in Illinois. See the full index history below.

Baltimore Oriole Population Forecast in Illinois

If the recent trend holds, Baltimore Oriole in Illinois is projected to rise about 20% by 2029 — from 2.2 in 2024 to a central estimate of 2.6 (95% range 1.3–3.9). A 5-year backtest shows a typical error of ±37.7%, with 100% of held-out values landing inside the 95% band.

+20%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 →
2.6Projected 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 →
1.3–3.995% 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 →
±37.7%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, Baltimore Oriole in Illinois is projected to rise about 20% by 2029 — from 2.2 in 2024 to a central estimate of 2.6 (95% range 1.3–3.9). A 5-year backtest shows a typical error of ±37.7%, 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 →
20252.61.33.9
20262.61.33.9
20272.61.33.9
20282.61.33.9
20292.61.33.9

Baltimore Oriole Survey Routes in Illinois

Routes recording Baltimore Oriole 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 →
Birds1520241977
Terre Haute1320241966
Camp Point1220231993
Marshall1220242001
Lake Galena920212001
Lake Summerset920222001
Belleview820241966
New Lenox720191966
Mill Creek620241966
Union620172001
Chandlervill520241971
Bartonville520241974
Caledonia520241993
York520241994
Payson520242000
Eubanks520242001
Guilford420231967
Holcomb420241977
Itasca420241973
Wayne420241966
Monica420171973
Deer Creek420241967
Humboldt420211972
Mt Vernon420141972
Belknap420221971

Baltimore Oriole Population Trend in Other States

alabamaarkansascaliforniacoloradoconnecticutdelawaregeorgiaindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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