Species · Illinois · BBS 2025 Release · 1966–2024
Marsh Wren Population Trend in Illinois
Marsh Wren in Illinois has collapsed: down 76% on the route-weighted index since 1979.
-76%Since 1979
10Routes In State
22Years
Notable Marsh Wren Trends in Illinois
long arc declinecomputed index
Marsh Wren has collapsed in Illinois: down 76% on the route-weighted index since 1979.
Marsh Wren Population Forecast in Illinois
If the recent trend holds, Marsh Wren in Illinois is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.04). A 5-year backtest shows a typical error of ±156.5%, with 100% of held-out values landing inside the 95% band.
n/aChange by 2029
0.00Projected 2029 index
0.00–0.0495% range
±156.5%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.00 | 0.00 | 0.05 |
| 2026 | 0.00 | 0.00 | 0.04 |
| 2027 | 0.00 | 0.00 | 0.04 |
| 2028 | 0.00 | 0.00 | 0.04 |
| 2029 | 0.00 | 0.00 | 0.04 |
Marsh Wren Survey Routes in Illinois
| New Lenox | 4 | 1982 | 1977 |
| Melrose | 3 | 1979 | 1979 |
| Barrington | 3 | 2011 | 1977 |
| Compton | 1 | 2017 | 2000 |
| Wayne | 1 | 2024 | 1985 |
| Sherburnvill | 1 | 2016 | 2016 |
| Sterling | 1 | 2009 | 2009 |
| Clayton | 1 | 2018 | 2016 |
| Chandlervill | 1 | 1985 | 1976 |
| Bartonville | 1 | 2019 | 2019 |
Marsh Wren Population Trend in Other States
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Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.