BirdAnalyst
Species · Illinois · BBS 2026 Release · 1966–2025

Orchard Oriole Population Trend in Illinois

All statesForest birds

Orchard Oriole in Illinois has surged: up 134% on the route-weighted index since 1968.

+134%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 →
98Routes 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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Orchard 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 →

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 →

Orchard Oriole has surged in Illinois: up 134% on the route-weighted index since 1968.

Orchard Oriole Population Forecast in Illinois

If the recent trend holds, Orchard Oriole in Illinois is projected to fall about 24% by 2030 — from 1.6 in 2025 to a central estimate of 1.2 (95% range 0.57–1.8). A 5-year backtest shows a typical error of ±21.6%, with 100% of held-out values landing inside the 95% band.

-24%Change by 2030TrendPercent 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 →
1.2Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.57–1.895% 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 →
±21.6%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, Orchard Oriole in Illinois is projected to fall about 24% by 2030 — from 1.6 in 2025 to a central estimate of 1.2 (95% range 0.57–1.8). A 5-year backtest shows a typical error of ±21.6%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20261.20.561.8
20271.20.561.8
20281.20.561.8
20291.20.571.8
20301.20.571.8

Orchard Oriole Survey Routes in Illinois

Routes recording Orchard 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 →
Belleview2720251966
Stillwell820251977
Sherrard520251998
Brownville520251993
Alden520232019
Janesville420251972
Bradbury420251970
Beaverdam Lk420231970
Robinson420231970
Eldred420251994
Darmstadt420232010
Cave In Rock420241993
Cherry Val320011979
Atkinson320241995
Putnam320241973
Buda320211995
Wayne320251969
Gulfport320251986
Milford320251966
Pulaski320251970
Delwood320251970
Troy Grove320232011
Clayton320252008
Athens320251996
Guilford220231977

Orchard Oriole Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.