BirdAnalyst
Species · Illinois · BBS 2025 Release · 1966–2024

Sedge Wren Population Trend in Illinois

All statesGrassland birds

Sedge Wren in Illinois has fallen sharply: down 55% on the route-weighted index since 1969.

-55%Since 1969TrendPercent 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 →
54Routes 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 →
52YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Sedge 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 →

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 →

Sedge Wren has fallen sharply in Illinois: down 55% on the route-weighted index since 1969.

Sedge Wren Population Forecast in Illinois

If the recent trend holds, Sedge Wren in Illinois is projected to rise about 58% by 2029 — from 0.05 in 2024 to a central estimate of 0.08 (95% range 0.00–0.21). A 5-year backtest shows a typical error of ±261.6%, with 100% of held-out values landing inside the 95% band.

+58%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 →
0.08Projected 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 →
0.00–0.2195% 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 →
±261.6%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, Sedge Wren in Illinois is projected to rise about 58% by 2029 — from 0.05 in 2024 to a central estimate of 0.08 (95% range 0.00–0.21). A 5-year backtest shows a typical error of ±261.6%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.080.000.21
20260.080.000.21
20270.080.000.21
20280.080.000.21
20290.080.000.21

Sedge Wren Survey Routes in Illinois

Routes recording Sedge 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 →
Mascoutah Lk820132008
New Lenox419841981
Milford419971991
Keithsburg420072006
Sherburnvill319741967
Monticello320072006
Martinsville319991999
Beaucoup320161989
Guilford220011977
Cherry Val219931993
Geneseo220001984
Wayne220231969
Bluff Spgs219981998
Fairland219851985
Lake Summerset220222003
Jamestown220131997
St Morgan220221990
Eubanks220162004
Dudleyville220172007
Caledonia220241998
Yale219991999
York220052000
Darmstadt220132013
Alden220222022
Mill Creek120091967

Sedge Wren Population Trend in Other States

connecticutdelawareindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanew-hampshirenew-yorknorth-dakotaohiopennsylvaniasouth-dakotavermontvirginiawisconsin

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