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

House Finch Population Trend in Illinois

All statesGeneralists

House Finch in Illinois has surged: up 30× on the route-weighted index since 1989.

30×Since 1989TrendPercent 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 →
38YearsYears 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 Finch 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 →

House Finch has surged in Illinois: up 30× on the route-weighted index since 1989.

House Finch Population Forecast in Illinois

If the recent trend holds, House Finch in Illinois is projected to fall about 24% by 2030 — from 6.2 in 2025 to a central estimate of 4.7 (95% range 1.4–8.0). A 5-year backtest shows a typical error of ±18.6%, with 100% of held-out values landing inside the 95% band.

-24%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 →
4.7Projected 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 →
1.4–8.095% 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 →
±18.6%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, House Finch in Illinois is projected to fall about 24% by 2030 — from 6.2 in 2025 to a central estimate of 4.7 (95% range 1.4–8.0). A 5-year backtest shows a typical error of ±18.6%, with 100% of held-out values landing inside the 95% band.19872030
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 →
20264.61.37.9
20274.61.37.9
20284.61.37.9
20294.71.48.0
20304.71.48.0

House Finch Survey Routes in Illinois

Routes recording House Finch 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 →
Harristown6220252001
Wayne4220251990
Itasca1920251988
Caledonia1920251994
Lake Summerset1920252001
Bartonville1820251992
Marshall1820252002
Janesville1720251992
Seneca1620251993
Belknap1520251993
Sheffield1420241991
New Lenox1420191988
Alden1220252019
Williamsfld1120251992
Pontiac1120251993
Union1120172001
Holcomb920251990
Monticello920251989
Dailey920251989
Cherry Val 2920182004
Grape Creek920252001
Buda820231994
Newark820221989
Cherry Val720031990
Mackinaw720251991

House Finch Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.