BirdAnalyst
Species · BCR 27 · BBS 2026 Release · 1966–2025

Chimney Swift In Southeastern Coastal Plain

All regionsSoutheastern Coastal PlainAerial insectivores

Chimney Swift in Southeastern Coastal Plain has fallen sharply: down 64% on the route-weighted index since 1968.

-64%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 →
343Routes 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 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 Southeastern Coastal Plain: down 64% on the route-weighted index since 1968.

Chimney Swift In Southeastern Coastal Plain Population Forecast

If the recent trend holds, Chimney Swift in Southeastern Coastal Plain is projected to stay roughly flat through 2030, near 4.9 (95% range 1.3–8.4). A 5-year backtest shows a typical error of ±32.1%, with 100% of held-out values landing inside the 95% band.

+3%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 →
4.9Projected 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 →
1.3–8.495% 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 →
±32.1%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, Chimney Swift in Southeastern Coastal Plain is projected to stay roughly flat through 2030, near 4.9 (95% range 1.3–8.4). A 5-year backtest shows a typical error of ±32.1%, with 100% 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 →
20265.52.09.1
20275.41.88.9
20285.21.68.8
20295.01.58.6
20304.91.38.4

Routes In Southeastern Coastal Plain

Routes recording Chimney Swift in Southeastern Coastal Plain.
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 →
SpeedNORTH-CAROLINA762025
GuytonGEORGIA441993
Adams RunSOUTH-CAROLINA342025
BeargrassNORTH-CAROLINA331981
ShallotteNORTH-CAROLINA311991
Boykin Ml PdSOUTH-CAROLINA301968
HowardALABAMA272025
RiderwoodALABAMA262023
DarienGEORGIA242019
Mt CarmelMISSISSIPPI222016
JamesvilleNORTH-CAROLINA212025
NewsomsVIRGINIA202024
SlidellLOUISIANA191988
LacombeLOUISIANA181983
Trace LeeMISSISSIPPI182018
FinleysonGEORGIA172025
California 2NORTH-CAROLINA172025
DortchesNORTH-CAROLINA172025
Chowan RiverNORTH-CAROLINA172006
CottonGEORGIA162025
TazewellGEORGIA162025
CowardSOUTH-CAROLINA162025
New HollandSOUTH-CAROLINA162025
BishopvilleSOUTH-CAROLINA162025
BaxleyGEORGIA152019

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