Species · Delaware · BBS 2025 Release · 1966–2024
Prairie Warbler Population Trend in Delaware
Prairie Warbler in Delaware has fallen sharply: down 63% on the route-weighted index since 1968.
-63%Since 1968
15Routes In State
55Years
Notable Prairie Warbler Trends in Delaware
long arc declinecomputed index
Prairie Warbler has fallen sharply in Delaware: down 62% on the route-weighted index since 1968.
Prairie Warbler Population Forecast in Delaware
If the recent trend holds, Prairie Warbler in Delaware is projected to rise about 173% by 2029 — from 0.20 in 2024 to a central estimate of 0.55 (95% range 0.00–1.6). A 5-year backtest shows a typical error of ±110.3%, with 100% of held-out values landing inside the 95% band.
+173%Change by 2029
0.55Projected 2029 index
0.00–1.695% range
±110.3%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.59 | 0.00 | 1.6 |
| 2026 | 0.58 | 0.00 | 1.6 |
| 2027 | 0.57 | 0.00 | 1.6 |
| 2028 | 0.56 | 0.00 | 1.6 |
| 2029 | 0.55 | 0.00 | 1.6 |
Prairie Warbler Survey Routes in Delaware
| Holleyville | 5 | 2004 | 1966 |
| Lowes Xrds | 5 | 1987 | 1966 |
| Pepperbox | 4 | 2016 | 1998 |
| Bethany Bch | 2 | 1989 | 1978 |
| Mt Pleasant | 1 | 1992 | 1966 |
| Wilmington | 1 | 2011 | 1968 |
| Harrington | 1 | 2024 | 1967 |
| Frederica | 1 | 2008 | 1967 |
| Dover | 1 | 1975 | 1975 |
| Frankford | 1 | 2008 | 1966 |
| Milton | 1 | 2008 | 1984 |
| Millsboro | 1 | 2021 | 2017 |
| Holleyville 2 | 1 | 2019 | 2006 |
| Georgetown | 1 | 2022 | 1992 |
| Pepperbox 2 | 1 | 2021 | 2019 |
Prairie Warbler Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.