BirdAnalyst
Species · BCR 27 · BBS 2025 Release · 1966–2024

Swainson's Warbler In Southeastern Coastal Plain

All regionsSoutheastern Coastal PlainForest birds

Swainson's Warbler in Southeastern Coastal Plain has surged: up 26× on the route-weighted index since 1968.

26×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 →
220Routes 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 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 →

Swainson's Warbler has surged in Southeastern Coastal Plain: up 26× on the route-weighted index since 1968.

Forecast

If the recent trend holds, Swainson's Warbler in Southeastern Coastal Plain is projected to fall about 24% by 2029 — from 0.67 in 2024 to a central estimate of 0.51 (95% range 0.38–0.64). A 5-year backtest shows a typical error of ±14.3%, with 80% of held-out values landing inside the 95% band.

-24%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 →
0.51Projected 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 →
0.38–0.6495% 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 →
±14.3%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, Swainson's Warbler in Southeastern Coastal Plain is projected to fall about 24% by 2029 — from 0.67 in 2024 to a central estimate of 0.51 (95% range 0.38–0.64). A 5-year backtest shows a typical error of ±14.3%, with 80% 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 →
20250.480.350.61
20260.490.360.61
20270.490.360.62
20280.500.370.63
20290.510.380.64

Routes In Southeastern Coastal Plain

Routes recording Swainson's Warbler 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 →
Sprott-Cahaba RivALABAMA342014
Gainestown FerryALABAMA172015
GreensboroALABAMA82024
HoltALABAMA82024
HowardALABAMA72024
Seminole Hills 2FLORIDA72022
New HopeFLORIDA62011
BloctonALABAMA52024
Trace LormanMISSISSIPPI52019
Dismal SwampNORTH-CAROLINA52024
LindenALABAMA42023
CottontonALABAMA42024
NewtonALABAMA42024
SouthALABAMA42024
BloxhamFLORIDA42022
DeepstepGEORGIA42023
Dismal SwampVIRGINIA42016
Warrior StdALABAMA32024
BrundidgeALABAMA32021
WedgeworthALABAMA32024
VernonALABAMA32022
Chacaloochee BayALABAMA32019
Miller XrdsFLORIDA32019
BristolFLORIDA32019
ColumbiaMISSISSIPPI32018

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