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Species · Illinois · BBS 2025 Release · 1966–2024

Henslow's Sparrow Population Trend in Illinois

All statesGrassland birds

Henslow's Sparrow in Illinois has risen sharply: up 51% on the route-weighted index since 1973.

+51%Since 1973
33Routes In State
39Years

Notable Henslow's Sparrow Trends in Illinois

long arc increasecomputed index

Henslow's Sparrow has risen sharply in Illinois: up 51% on the route-weighted index since 1973.

Henslow's Sparrow Population Forecast in Illinois

If the recent trend holds, Henslow's Sparrow in Illinois is projected to rise about 10% by 2029 — from 0.07 in 2024 to a central estimate of 0.07 (95% range 0.01–0.14). A 5-year backtest shows a typical error of ±15.9%, with 100% of held-out values landing inside the 95% band.

+10%Change by 2029
0.07Projected 2029 index
0.01–0.1495% range
±15.9%Backtest error
19692029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected index95% low95% high
20250.070.010.13
20260.070.010.13
20270.070.010.14
20280.070.010.14
20290.070.010.14

Henslow's Sparrow Survey Routes in Illinois

Routes recording Henslow's Sparrow in Illinois.
Alden420192019
Buda320162003
Milford320132013
Wayne220222010
Fairbury220232022
Bluff Spgs220222022
Sterling220082008
Grape Creek220052005
Delwood220241988
Guilford120171969
Mill Creek120072007
Geneseo119731973
Sheffield120242024
Compton119731973
Streator120242013
Newark120152015
New Lenox119801971
Terre Haute120062006
Mackinaw120171983
Pontiac120022002
Belleview119891989
Rosamond120072007
Lake Galena120122002
Clayton120242024
Gridley120232018

Henslow's Sparrow Population Trend in Other States

delawareindianaiowakansaskentuckymarylandmichiganminnesotamissourinebraskanew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniasouth-dakotavermontvirginiawest-virginiawisconsin

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