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Species · Illinois · BBS 2025 Release · 1966–2024

Grasshopper Sparrow Population Trend in Illinois

All statesGrassland birds

Grasshopper Sparrow in Illinois has collapsed: down 94% on the route-weighted index since 1968.

-94%Since 1968
99Routes In State
58Years

Notable Grasshopper Sparrow Trends in Illinois

long arc declinecomputed index

Grasshopper Sparrow has collapsed in Illinois: down 94% on the route-weighted index since 1968.

Grasshopper Sparrow Population Forecast in Illinois

If the recent trend holds, Grasshopper Sparrow in Illinois is projected to fall about 100% by 2029 — from 0.45 in 2024 to a central estimate of 0.00 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±46.3%, with 100% of held-out values landing inside the 95% band.

-100%Change by 2029
0.00Projected 2029 index
0.00–1.795% range
±46.3%Backtest error
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 index95% low95% high
20250.260.001.9
20260.180.001.8
20270.100.001.8
20280.020.001.7
20290.000.001.7

Grasshopper Sparrow Survey Routes in Illinois

Routes recording Grasshopper Sparrow in Illinois.
Clayton820192003
Duncan Mills720241993
Greenview520241993
New Lenox419901966
Martinsville420131976
Shannon419941993
York420241993
Cave In Rock420171997
Lake Galena420212002
Royalton420242001
Karnak420152001
Guilford320111968
Fairbury320241976
Beaucoup320211972
Cherry Val219961976
Putnam220191972
Essex220011969
Stillwell220241971
Terre Haute220241966
Monica220111973
Melrose219991973
Concord220111967
Pawnee220181967
Humboldt220081970
Mascoutah Lk220191978

Grasshopper Sparrow Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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