Species · Illinois · BBS 2025 Release · 1966–2024
Prothonotary Warbler Population Trend in Illinois
Prothonotary Warbler in Illinois has surged: up 234% on the route-weighted index since 1968.
+234%Since 1968
36Routes In State
58Years
Notable Prothonotary Warbler Trends in Illinois
long arc increasecomputed index
Prothonotary Warbler has surged in Illinois: up 234% on the route-weighted index since 1968.
Prothonotary Warbler Population Forecast in Illinois
If the recent trend holds, Prothonotary Warbler in Illinois is projected to fall about 19% by 2029 — from 0.33 in 2024 to a central estimate of 0.27 (95% range 0.12–0.43). A 5-year backtest shows a typical error of ±59.9%, with 40% of held-out values landing inside the 95% band.
-19%Change by 2029
0.27Projected 2029 index
0.12–0.4395% range
±59.9%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.26 | 0.10 | 0.41 |
| 2026 | 0.26 | 0.11 | 0.42 |
| 2027 | 0.27 | 0.11 | 0.42 |
| 2028 | 0.27 | 0.11 | 0.42 |
| 2029 | 0.27 | 0.12 | 0.43 |
Prothonotary Warbler Survey Routes in Illinois
| Pulaski | 9 | 2024 | 1970 |
| Beaverdam Lk | 7 | 2023 | 1970 |
| Belleview | 5 | 2024 | 1966 |
| Belknap | 5 | 2024 | 1973 |
| Birds | 3 | 2024 | 1978 |
| Karnak | 3 | 2023 | 2003 |
| Eldred | 3 | 1995 | 1995 |
| Newark | 2 | 2014 | 2014 |
| Mascoutah Lk | 2 | 2023 | 1981 |
| Athens | 1 | 2015 | 2015 |
| Geneseo | 1 | 2018 | 1971 |
| Gulfport | 1 | 2023 | 2023 |
| Chandlervill | 1 | 1973 | 1973 |
| Athensville | 1 | 2003 | 1979 |
| Concord | 1 | 2004 | 1983 |
| Pawnee | 1 | 2002 | 1979 |
| Fairland | 1 | 1994 | 1994 |
| Lake Summerset | 1 | 2012 | 2012 |
| Humboldt | 1 | 2023 | 2023 |
| Columbia | 1 | 1968 | 1968 |
| Jamestown | 1 | 2012 | 1971 |
| St Morgan | 1 | 2022 | 1969 |
| Beaucoup | 1 | 2023 | 1994 |
| Brnt Prairie | 1 | 2023 | 1987 |
| Yorkville | 1 | 2009 | 2009 |
Prothonotary Warbler Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.