BirdAnalyst
Species · Illinois · BBS 2026 Release · 1966–2025

House Sparrow Population Trend in Illinois

All statesGeneralists

House Sparrow in Illinois has collapsed: down 81% on the route-weighted index since 1968.

-81%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 House Sparrow 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 declinecomputed 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 →

House Sparrow has collapsed in Illinois: down 81% on the route-weighted index since 1968.

House Sparrow Population Forecast in Illinois

If the recent trend holds, House Sparrow in Illinois is projected to fall about 100% by 2030 — from 54 in 2025 to a central estimate of 0.00 (95% range 0.00–42). A 5-year backtest shows a typical error of ±85.3%, with 20% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–4295% 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 →
±85.3%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, House Sparrow in Illinois is projected to fall about 100% by 2030 — from 54 in 2025 to a central estimate of 0.00 (95% range 0.00–42). A 5-year backtest shows a typical error of ±85.3%, with 20% 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 →
20268.50.0051
20274.00.0046
20280.000.0042
20290.000.0042
20300.000.0042

House Sparrow Survey Routes in Illinois

Routes recording House Sparrow 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 →
Itasca29320251966
Atkinson22920241966
Marshall21320252001
Wayne17720251966
Humboldt15220251970
Terre Haute14820251966
Sterling14220232001
Sheffield13820241966
Streator10120251972
Beaucoup10020251971
York10020251993
Barrington9920121967
Yale9920251993
Bartonville8820251973
Harristown8820252001
Holcomb8720251971
Bradbury8720251970
Newark8420221969
St Morgan8120221967
Mackinaw7520251966
Geneseo7420251967
Caledonia7420251993
Seneca6920251993
Compton6720251968
Le Roy6720251993

House Sparrow 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.