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

Broad-winged Hawk Population Trend in Illinois

All statesGeneralists

Broad-winged Hawk in Illinois has declined: down 29% on the route-weighted index since 1974.

-29%Since 1974TrendPercent 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 →
13Routes 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 →
20YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Broad-winged 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 →

No notable trend signals for Broad-winged Hawk in Illinois. See the full index history below.

Broad-winged Hawk Population Forecast in Illinois

If the recent trend holds, Broad-winged Hawk in Illinois is projected to stay roughly flat through 2028, near 0.01 (95% range 0.00–0.03). A 5-year backtest shows a typical error of ±42.6%, with 80% of held-out values landing inside the 95% band.

n/aChange by 2028TrendPercent 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 →
0.01Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.0395% 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 →
±42.6%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, Broad-winged Hawk in Illinois is projected to stay roughly flat through 2028, near 0.01 (95% range 0.00–0.03). A 5-year backtest shows a typical error of ±42.6%, with 80% of held-out values landing inside the 95% band.19682028
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 →
20240.020.000.04
20250.020.000.04
20260.020.000.03
20270.010.000.03
20280.010.000.03

Broad-winged Hawk Survey Routes in Illinois

Routes recording Broad-winged 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 →
Wayne219981998
Dudleyville220132013
Pulaski220222006
Royalton120042004
Guilford119901984
Mill Creek119971997
Belleview119961993
Sandusky120002000
Cave In Rock120232000
New Lenox119681968
Bremen120181998
Delwood119961996
Beaverdam Lk119741970

Broad-winged Hawk Population Trend in Other States

alabamaarkansasconnecticutdelawarefloridageorgiaindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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