Species · Pennsylvania · BBS 2025 Release · 1966–2024
Alder Flycatcher Population Trend in Pennsylvania
Alder Flycatcher in Pennsylvania has surged: up 287% on the route-weighted index since 1973.
+287%Since 1973
78Routes In State
53Years
Notable Alder Flycatcher Trends in Pennsylvania
long arc increasecomputed index
Alder Flycatcher has surged in Pennsylvania: up 287% on the route-weighted index since 1973.
Alder Flycatcher Population Forecast in Pennsylvania
If the recent trend holds, Alder Flycatcher in Pennsylvania is projected to rise about 75% by 2029 — from 0.35 in 2024 to a central estimate of 0.61 (95% range 0.34–0.87). A 5-year backtest shows a typical error of ±79.2%, with 20% of held-out values landing inside the 95% band.
+75%Change by 2029
0.61Projected 2029 index
0.34–0.8795% range
±79.2%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.57 | 0.31 | 0.84 |
| 2026 | 0.58 | 0.32 | 0.84 |
| 2027 | 0.59 | 0.33 | 0.85 |
| 2028 | 0.60 | 0.34 | 0.86 |
| 2029 | 0.61 | 0.34 | 0.87 |
Alder Flycatcher Survey Routes in Pennsylvania
| Little Marsh | 8 | 2023 | 1993 |
| Roulette 2 | 7 | 2023 | 2022 |
| Eldred | 6 | 2015 | 1990 |
| Roulette | 5 | 2021 | 1988 |
| Rasselas | 4 | 2022 | 1999 |
| Logue | 4 | 2023 | 1981 |
| Marsh Hill | 4 | 2024 | 1991 |
| Starlight | 4 | 1992 | 1992 |
| Greentown | 4 | 2024 | 1977 |
| Ellenton | 4 | 2024 | 1982 |
| Rush | 3 | 2024 | 1971 |
| Poyntelle | 3 | 2024 | 1993 |
| Sugar Grove | 3 | 2024 | 1995 |
| Ferris Crnrs | 2 | 2024 | 1973 |
| Whig Hill | 2 | 2003 | 1989 |
| Akeley | 2 | 1976 | 1974 |
| Teepleville | 2 | 2023 | 1995 |
| N Pine Grove | 2 | 1997 | 1997 |
| Betula | 2 | 2022 | 1987 |
| Arnot | 2 | 2024 | 1982 |
| Mawr Glen | 2 | 2019 | 1985 |
| Austinville | 2 | 2024 | 1982 |
| New Ringgold | 2 | 1985 | 1979 |
| Mars | 2 | 1994 | 1994 |
| Espyville | 1 | 2013 | 1975 |
Alder Flycatcher Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.