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

Turkey Vulture Population Trend in Illinois

All statesBirds of prey

Turkey Vulture in Illinois has surged: up 55× on the route-weighted index since 1972.

55×Since 1972TrendPercent 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 →
103Routes 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 →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Turkey Vulture 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 →

Turkey Vulture has surged in Illinois: up 55× on the route-weighted index since 1972.

Turkey Vulture Population Forecast in Illinois

If the recent trend holds, Turkey Vulture in Illinois is projected to fall about 14% by 2030 — from 7.1 in 2025 to a central estimate of 6.1 (95% range 4.3–8.0). A 5-year backtest shows a typical error of ±24.8%, with 60% of held-out values landing inside the 95% band.

-14%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 →
6.1Projected 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 →
4.3–8.095% 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 →
±24.8%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, Turkey Vulture in Illinois is projected to fall about 14% by 2030 — from 7.1 in 2025 to a central estimate of 6.1 (95% range 4.3–8.0). A 5-year backtest shows a typical error of ±24.8%, with 60% of held-out values landing inside the 95% band.19672030
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 →
20265.63.87.5
20275.83.97.6
20285.94.07.7
20296.04.17.8
20306.14.38.0

Turkey Vulture Survey Routes in Illinois

Routes recording Turkey Vulture 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 →
Payson6020252000
Chandlervill5320251971
Terre Haute3220251984
Belleview3220251974
Karnak3220252001
Royalton3120252001
York2220251993
Pulaski1920251977
Robinson1920231976
Eldred1920251993
Sandusky1820231996
Janesville1720251974
Bremen1720251972
Sheffield1520241988
Cave In Rock1520241993
Nilwood1420231993
Concord1320251967
Columbia1320251989
Belknap1220251972
Holcomb1120251989
Athensville1120251991
Duncan Mills1120251995
Geneseo1020171985
Gulfport1020251990
Monica1020171997

Turkey Vulture Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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