Species · Pennsylvania · BBS 2025 Release · 1966–2024

Chestnut-sided Warbler Population Trend in Pennsylvania

Chestnut-sided Warbler in Pennsylvania has surged: up 107% on the route-weighted index since 1968.

+107%Since 1968
112Routes In State
58Years

Notable Chestnut-sided Warbler Trends in Pennsylvania

long arc increasecomputed index

Chestnut-sided Warbler has surged in Pennsylvania: up 107% on the route-weighted index since 1968.

Chestnut-sided Warbler Population Forecast in Pennsylvania

If the recent trend holds, Chestnut-sided Warbler in Pennsylvania is projected to rise about 13% by 2029 — from 4.3 in 2024 to a central estimate of 4.9 (95% range 3.7–6.1). A 5-year backtest shows a typical error of ±16.6%, with 80% of held-out values landing inside the 95% band.

+13%Change by 2029
4.9Projected 2029 index
3.76.195% range
±16.6%Backtest error
19662029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected index95% low95% high
20254.73.55.8
20264.73.65.9
20274.83.65.9
20284.83.76.0
20294.93.76.1

Chestnut-sided Warbler Survey Routes in Pennsylvania

Routes recording Chestnut-sided Warbler in Pennsylvania.
Odin4820241975
Roulette2820211970
Eldred2520221974
Poyntelle2520241969
Duboistown2220241987
Susquehanna2120241971
Sugar Grove1920241981
Starlight1819991970
Sproul Sf-A1820242002
Roulette 21720242022
Laurel Hill1620241978
Sproul Sf-B1420242002
Ridgway1320181967
Honesdale1220241972
Marsh Hill1120241985
Mill Run1120241978
Betula1020221973
Cherry Sprs1020231974
Logue920231970
Starlight 2920242000
Ansonia920242002
Arnot820241969
Greentown820241973
Munson820241980
Ellenton820241982

Chestnut-sided Warbler Population Trend in Other States

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.