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Species · Illinois · BBS 2026 Release · 1966–2025

Northern House Wren Population Trend in Illinois

All statesForest birds

Northern House Wren in Illinois has increased: up 43% on the route-weighted index since 1968.

+43%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 →
103Routes 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 Northern House Wren 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 Northern House Wren in Illinois. See the full index history below.

Northern House Wren Population Forecast in Illinois

If the recent trend holds, Northern House Wren in Illinois is projected to stay roughly flat through 2030, near 12 (95% range 8.9–14). A 5-year backtest shows a typical error of ±10.1%, with 100% of held-out values landing inside the 95% band.

+1%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 →
12Projected 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 →
8.9–1495% 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 →
±10.1%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, Northern House Wren in Illinois is projected to stay roughly flat through 2030, near 12 (95% range 8.9–14). A 5-year backtest shows a typical error of ±10.1%, with 100% 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 →
2026118.514
2027118.614
2028118.714
2029128.814
2030128.914

Northern House Wren Survey Routes in Illinois

Routes recording Northern House Wren 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 →
Union4120172001
Sheffield3920241966
Lake Summerset3320252001
Caledonia3020251993
Buda2620231977
Harristown2620252001
Mill Creek2520251966
Sherrard2520251993
Bartonville2420251973
Holcomb2320251971
Sterling2220232001
Atkinson2120241966
Geneseo2120251967
Deer Creek2120241966
Humboldt2120251970
Fairdale2120252019
New Lenox2020191966
Terre Haute2020251966
Concord1920251967
Pontiac1820251978
Janesville1820251975
Grape Creek1820252001
Eubanks1820252001
Seneca1720251993
Gulfport1620251971

Northern House Wren Population Trend in Other States

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

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