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Species · Illinois · BBS 2026 Release · 1966–2025

Red-tailed Hawk Population Trend in Illinois

All statesBirds of prey

Red-tailed Hawk in Illinois has surged: up 138% on the route-weighted index since 1968.

+138%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 →
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 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 138% 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 80% by 2030 — from 1.2 in 2025 to a central estimate of 2.1 (95% range 1.4–2.8). A 5-year backtest shows a typical error of ±37.5%, with 60% of held-out values landing inside the 95% band.

+80%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 →
2.1Projected 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 →
1.4–2.895% 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 →
±37.5%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, Red-tailed Hawk in Illinois is projected to rise about 80% by 2030 — from 1.2 in 2025 to a central estimate of 2.1 (95% range 1.4–2.8). A 5-year backtest shows a typical error of ±37.5%, with 60% 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 →
20262.01.32.7
20272.01.42.7
20282.11.42.8
20292.11.42.8
20302.11.42.8

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 →
Holcomb720251979
Darmstadt720251994
Monica520171981
Pontiac520231995
Athensville520251974
Humboldt520241984
Atkinson420241966
Sheffield420241966
Fairbury420251980
Bradbury420241986
Mascoutah Lk420251967
Seneca420241993
Eldred420211993
Brownville420231993
Lake Summerset420252001
Dudleyville420252001
Buda320231979
Newark320221982
Sherburnvill320231975
New Lenox320191966
Chandlervill320251973
Terre Haute320251971
Jamestown320251982
Brnt Prairie320251978
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 2026-08-14.