BirdAnalyst
Species · BCR 29 · BBS 2025 Release · 1966–2024

Swainson's Warbler In Piedmont

All regionsPiedmontForest birds

Swainson's Warbler in Piedmont has surged: up 483% on the route-weighted index since 1981.

+483%Since 1981TrendPercent 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 →
31Routes 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 →
29YearsYears 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 Piedmont: up 483% on the route-weighted index since 1981.

Swainson's Warbler In Piedmont Population Forecast

If the recent trend holds, Swainson's Warbler in Piedmont is projected to fall about 13% by 2029 — from 0.10 in 2024 to a central estimate of 0.09 (95% range 0.03–0.15). A 5-year backtest shows a typical error of ±64.6%, with 0% of held-out values landing inside the 95% band.

-13%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 →
0.09Projected 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 →
0.03–0.1595% 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 →
±64.6%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, Swainson's Warbler in Piedmont is projected to fall about 13% by 2029 — from 0.10 in 2024 to a central estimate of 0.09 (95% range 0.03–0.15). A 5-year backtest shows a typical error of ±64.6%, with 0% of held-out values landing inside the 95% band.19792029
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 →
20250.080.020.14
20260.080.020.14
20270.080.020.14
20280.090.020.15
20290.090.030.15

Routes In Piedmont

Routes recording Swainson's Warbler in Piedmont.
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 →
Liberty City 2ALABAMA32024
MillervilleALABAMA22024
Yates CrossroadsGEORGIA22023
Plum BranchSOUTH-CAROLINA21988
LanettALABAMA12024
Liberty CityALABAMA12005
Nixburg 2ALABAMA12021
WedoweeALABAMA12023
ForsythGEORGIA12024
BaldwinGEORGIA11981
GrovetownGEORGIA12019
BowdonGEORGIA12007
StockbridgeGEORGIA11985
RutledgeGEORGIA12024
JulietteGEORGIA12023
WhitesburgGEORGIA12015
Lincolnton 2GEORGIA12022
SharonGEORGIA12018
Sunny SideGEORGIA12019
Rock BranchGEORGIA12022
Stoney Point 2GEORGIA12022
Piedmont NwrGEORGIA11991
JordanNORTH-CAROLINA11979
OakboroNORTH-CAROLINA12024
ArcolaNORTH-CAROLINA12000

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