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

Red-shouldered Hawk Population Trend in Illinois

All statesGeneralists

Red-shouldered Hawk in Illinois has surged: up 21× on the route-weighted index since 1969.

21×Since 1969TrendPercent 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 →
51Routes 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 →
56YearsYears 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-shouldered 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-shouldered Hawk has surged in Illinois: up 21× on the route-weighted index since 1969.

Red-shouldered Hawk Population Forecast in Illinois

If the recent trend holds, Red-shouldered Hawk in Illinois is projected to fall about 37% by 2029 — from 0.87 in 2024 to a central estimate of 0.55 (95% range 0.15–0.94). A 5-year backtest shows a typical error of ±54.5%, with 20% of held-out values landing inside the 95% band.

-37%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 →
0.55Projected 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 →
0.15–0.9495% 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 →
±54.5%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-shouldered Hawk in Illinois is projected to fall about 37% by 2029 — from 0.87 in 2024 to a central estimate of 0.55 (95% range 0.15–0.94). A 5-year backtest shows a typical error of ±54.5%, with 20% 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 →
20250.510.110.90
20260.520.120.91
20270.530.130.92
20280.540.140.93
20290.550.150.94

Red-shouldered Hawk Survey Routes in Illinois

Routes recording Red-shouldered 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 →
Beaverdam Lk1320231970
Delwood1120241970
Mt Vernon720241990
Belknap720241983
Royalton520242008
Birds420222022
Pulaski420241970
Robinson420232021
Marshall420242013
Dudleyville420242001
York420242001
Cave In Rock420242001
Athens220162016
Clayton220232023
Pawnee220232023
Bradbury220242005
Martinsville220222022
Columbia220212021
Mascoutah Lk220241991
St Morgan220221988
Olney220241966
Bremen220241984
Kell220242022
Karnak220242006
Yale220231996

Red-shouldered Hawk Population Trend in Other States

alabamaarkansascaliforniaconnecticutdelawarefloridageorgiaindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinatennesseetexasvermontvirginiawashingtonwest-virginiawisconsin

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