Species · Iowa · BBS 2025 Release · 1966–2024
Swamp Sparrow Population Trend in Iowa
Swamp Sparrow in Iowa has fallen sharply: down 59% on the route-weighted index since 1974.
-59%Since 1974
14Routes In State
26Years
Notable Swamp Sparrow Trends in Iowa
long arc declinecomputed index
Swamp Sparrow has fallen sharply in Iowa: down 59% on the route-weighted index since 1974.
Swamp Sparrow Population Forecast in Iowa
If the recent trend holds, Swamp Sparrow in Iowa is projected to stay roughly flat through 2029, near 0.04 (95% range 0.00–0.13). A 5-year backtest shows a typical error of ±53.6%, with 80% of held-out values landing inside the 95% band.
n/aChange by 2029
0.04Projected 2029 index
0.00–0.1395% range
±53.6%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.04 | 0.00 | 0.14 |
| 2026 | 0.04 | 0.00 | 0.14 |
| 2027 | 0.04 | 0.00 | 0.13 |
| 2028 | 0.04 | 0.00 | 0.13 |
| 2029 | 0.04 | 0.00 | 0.13 |
Swamp Sparrow Survey Routes in Iowa
| Scranton | 3 | 2003 | 1978 |
| Burchinal | 2 | 2003 | 2003 |
| Titonka | 1 | 1983 | 1983 |
| Rock Valley | 1 | 2019 | 2019 |
| Bryant | 1 | 2013 | 2013 |
| Cedar Valley | 1 | 1983 | 1983 |
| Williamsburg | 1 | 1997 | 1993 |
| Prairieburg | 1 | 1992 | 1990 |
| Hudson | 1 | 1982 | 1982 |
| Kanawha | 1 | 2024 | 1973 |
| Zearing | 1 | 1977 | 1977 |
| Clare | 1 | 1976 | 1976 |
| Davis Corner | 1 | 1989 | 1977 |
| Garner | 1 | 1993 | 1971 |
Swamp Sparrow Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.