BirdAnalyst
Species · BCR 28 · BBS 2026 Release · 1966–2025

Chestnut-sided Warbler In Appalachian Mountains

All regionsAppalachian MountainsForest birds

Chestnut-sided Warbler in Appalachian Mountains has surged: up 121% on the route-weighted index since 1968.

+121%Since 1968TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
261Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Chestnut-sided Warbler has surged in Appalachian Mountains: up 121% on the route-weighted index since 1968.

Chestnut-sided Warbler In Appalachian Mountains Population Forecast

If the recent trend holds, Chestnut-sided Warbler in Appalachian Mountains is projected to rise about 13% by 2030 — from 3.2 in 2025 to a central estimate of 3.6 (95% range 2.9–4.3). A 5-year backtest shows a typical error of ±15.1%, with 80% of held-out values landing inside the 95% band.

+13%Change by 2030TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
3.6Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
2.9–4.395% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±15.1%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Chestnut-sided Warbler in Appalachian Mountains is projected to rise about 13% by 2030 — from 3.2 in 2025 to a central estimate of 3.6 (95% range 2.9–4.3). A 5-year backtest shows a typical error of ±15.1%, with 80% of held-out values landing inside the 95% band.19662030
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20263.52.84.2
20273.52.84.2
20283.52.94.2
20293.62.94.3
20303.62.94.3

Routes In Appalachian Mountains

Routes recording Chestnut-sided Warbler in Appalachian Mountains.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Valley HeadWEST-VIRGINIA432025
N. Mills RivNORTH-CAROLINA381995
OdinPENNSYLVANIA382025
PoyntellePENNSYLVANIA342025
FinzelMARYLAND282025
RoulettePENNSYLVANIA282021
OneontaNEW-YORK262025
CattaraugusNEW-YORK262019
EldredPENNSYLVANIA252022
Platte CoveNEW-YORK242018
S Berne 2NEW-YORK242025
McdonoughNEW-YORK232017
LoguePENNSYLVANIA222025
DuboistownPENNSYLVANIA222024
AnsoniaPENNSYLVANIA192025
MeridaleNEW-YORK182025
StarlightPENNSYLVANIA181999
S BerneNEW-YORK172013
CullowheeNORTH-CAROLINA172025
Iron Mountain 2VIRGINIA162013
DrydenNEW-YORK152025
DownsvilleNEW-YORK152019
MilfordNEW-YORK152023
Oxford 2NEW-YORK152024
HonesdalePENNSYLVANIA152025

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.