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Species · Illinois · BBS 2025 Release · 1966–2024

Northern House Wren Population Trend in Illinois

All statesForest birds

Northern House Wren in Illinois has increased: up 46% on the route-weighted index since 1968.

+46%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 →
58YearsYears 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 2029, near 11 (95% range 8.7–14). A 5-year backtest shows a typical error of ±14.4%, with 60% of held-out values landing inside the 95% band.

+3%Change by 2029TrendPercent 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 →
11Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
8.7–1495% 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 →
±14.4%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 2029, near 11 (95% range 8.7–14). A 5-year backtest shows a typical error of ±14.4%, with 60% of held-out values landing inside the 95% band.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 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 →
2025118.414
2026118.514
2027118.514
2028118.614
2029118.714

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 Summerset3820222001
Alden3420232019
Bartonville3120241973
Buda2620231977
Terre Haute2620241966
Pontiac2320241978
Milford2220231966
Sterling2220232001
Atkinson2120241966
Deer Creek2120241966
Janesville2120241975
Sherrard2120241993
New Lenox2020191966
Cameron2020241966
Seneca2020241993
Stillwell1920241971
Eubanks1820242001
Harristown1820242001
Fairland1720241968
Mill Creek1620241966
Williamsfld1620241973
Shannon1620241993
Caledonia1620241993

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 2026-05-22.