BirdAnalyst
Species · BCR 28 · BBS 2025 Release · 1966–2024

Chimney Swift In Appalachian Mountains

All regionsAppalachian MountainsAerial insectivores

Chimney Swift in Appalachian Mountains has fallen sharply: down 54% on the route-weighted index since 1968.

-54%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 →
396Routes 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 →
58YearsYears 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 declinecomputed 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 →

Chimney Swift has fallen sharply in Appalachian Mountains: down 54% on the route-weighted index since 1968.

Chimney Swift In Appalachian Mountains Population Forecast

If the recent trend holds, Chimney Swift in Appalachian Mountains is projected to stay roughly flat through 2029, near 4.8 (95% range 2.1–7.5). A 5-year backtest shows a typical error of ±6%, with 100% of held-out values landing inside the 95% band.

-5%Change by 2029TrendPercent 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 →
4.8Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
2.1–7.595% 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 →
±6%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, Chimney Swift in Appalachian Mountains is projected to stay roughly flat through 2029, near 4.8 (95% range 2.1–7.5). A 5-year backtest shows a typical error of ±6%, with 100% of held-out values landing inside the 95% band.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 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 →
20255.32.68.0
20265.22.57.9
20275.02.37.7
20284.92.27.6
20294.82.17.5

Routes In Appalachian Mountains

Routes recording Chimney Swift 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 →
BirminghamALABAMA1451995
ClimerTENNESSEE522004
WilliamsportMARYLAND482024
RydePENNSYLVANIA472005
DearmanvilleALABAMA451983
Corryton RdTENNESSEE442019
ParkwoodPENNSYLVANIA422024
McdonaldWEST-VIRGINIA422023
Coal RunOHIO411992
PortersvillePENNSYLVANIA401988
HopeNEW-JERSEY391994
BloomsburyNEW-JERSEY382024
ArleeWEST-VIRGINIA361979
NewcomerstwnOHIO351995
WakenaPENNSYLVANIA322023
PattonPENNSYLVANIA312024
MidvaleNEW-JERSEY292022
StonecreekOHIO282024
KittanningPENNSYLVANIA282024
FayettevilleWEST-VIRGINIA281996
Plesant GrovPENNSYLVANIA272024
StaffordsvilKENTUCKY261997
DoylesburgPENNSYLVANIA252023
MartinsburgPENNSYLVANIA242024
SummittALABAMA231981

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