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

Red-tailed Hawk Population Trend in Illinois

All statesGeneralists

Red-tailed Hawk in Illinois has surged: up 178% on the route-weighted index since 1968.

+178%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 Red-tailed Hawk 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 →

Red-tailed Hawk has surged in Illinois: up 178% on the route-weighted index since 1968.

Red-tailed Hawk Population Forecast in Illinois

If the recent trend holds, Red-tailed Hawk in Illinois is projected to rise about 57% by 2029 — from 1.4 in 2024 to a central estimate of 2.2 (95% range 1.5–2.8). A 5-year backtest shows a typical error of ±37.1%, with 60% of held-out values landing inside the 95% band.

+57%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 →
2.2Projected 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 →
1.5–2.895% 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 →
±37.1%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, Red-tailed Hawk in Illinois is projected to rise about 57% by 2029 — from 1.4 in 2024 to a central estimate of 2.2 (95% range 1.5–2.8). A 5-year backtest shows a typical error of ±37.1%, with 60% 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 →
20252.01.42.7
20262.11.42.7
20272.11.42.8
20282.11.52.8
20292.21.52.8

Red-tailed Hawk Survey Routes in Illinois

Routes recording Red-tailed Hawk 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 →
Janesville620241993
Wayne520241974
Monica520171981
Fairbury520241980
Pontiac520231995
Humboldt520241984
Dudleyville520242001
Royalton520242001
Atkinson420241966
Sheffield420241966
Mackinaw420241996
Bradbury420241986
Seneca420241993
Eldred420211993
Brownville420231993
Buda320231979
Newark320221982
Sherburnvill320231975
New Lenox320191966
Monticello320241988
Athensville320231974
Humphrey320221988
Fairland320241972
Martinsville320241972
Beaverdam Lk320231974

Red-tailed Hawk Population Trend in Other States

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

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