Species · Maryland · BBS 2025 Release · 1966–2024
Prothonotary Warbler Population Trend in Maryland
Prothonotary Warbler in Maryland has surged: up 129% on the route-weighted index since 1968.
+129%Since 1968
36Routes In State
58Years
Notable Prothonotary Warbler Trends in Maryland
long arc increasecomputed index
Prothonotary Warbler has surged in Maryland: up 129% on the route-weighted index since 1968.
Prothonotary Warbler Population Forecast in Maryland
If the recent trend holds, Prothonotary Warbler in Maryland is projected to rise about 15% by 2029 — from 0.62 in 2024 to a central estimate of 0.71 (95% range 0.37–1.0). A 5-year backtest shows a typical error of ±19.2%, with 80% of held-out values landing inside the 95% band.
+15%Change by 2029
0.71Projected 2029 index
0.37–1.095% range
±19.2%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.69 | 0.35 | 1.0 |
| 2026 | 0.69 | 0.36 | 1.0 |
| 2027 | 0.70 | 0.36 | 1.0 |
| 2028 | 0.70 | 0.37 | 1.0 |
| 2029 | 0.71 | 0.37 | 1.0 |
Prothonotary Warbler Survey Routes in Maryland
| Berlin | 7 | 2024 | 1980 |
| Cokesbury | 5 | 2024 | 1972 |
| Furnace Town | 5 | 2024 | 2015 |
| Honga | 3 | 2024 | 1966 |
| Sinepuxent | 3 | 1977 | 1973 |
| Snow Hill | 3 | 1976 | 1966 |
| Indiantown | 2 | 2014 | 1977 |
| Earlton | 2 | 2019 | 2014 |
| Piney Neck | 2 | 2017 | 1972 |
| Harmony | 2 | 2017 | 1966 |
| Davidsnville | 2 | 2023 | 1993 |
| Island Creek | 2 | 2024 | 2001 |
| Williamsport | 1 | 2024 | 2017 |
| Olney | 1 | 2002 | 2002 |
| Walnut | 1 | 2005 | 1999 |
| Van Bibber | 1 | 2011 | 1967 |
| Largo | 1 | 1975 | 1967 |
| Cheltenham | 1 | 1966 | 1966 |
| Broomes Isl | 1 | 1989 | 1966 |
| Pt Republic | 1 | 1989 | 1986 |
| La Plata | 1 | 2009 | 1966 |
| Hughesville | 1 | 2023 | 2023 |
| Pomonkey | 1 | 2024 | 1967 |
| Pomfret | 1 | 2023 | 1966 |
| Theodore | 1 | 1968 | 1968 |
Prothonotary Warbler Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.