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

Tree Swallow In Southeastern Coastal Plain

All regionsSoutheastern Coastal PlainAerial insectivores

Tree Swallow in Southeastern Coastal Plain has surged: up 529% on the route-weighted index since 1982.

+529%Since 1982TrendPercent 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 →
59Routes 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 →
36YearsYears 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 →

Tree Swallow has surged in Southeastern Coastal Plain: up 529% on the route-weighted index since 1982.

Tree Swallow In Southeastern Coastal Plain Population Forecast

If the recent trend holds, Tree Swallow in Southeastern Coastal Plain is projected to fall about 51% by 2029 — from 0.12 in 2024 to a central estimate of 0.06 (95% range 0.02–0.10). A 5-year backtest shows a typical error of ±42.1%, with 60% of held-out values landing inside the 95% band.

-51%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 →
0.06Projected 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 →
0.02–0.1095% 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 →
±42.1%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, Tree Swallow in Southeastern Coastal Plain is projected to fall about 51% by 2029 — from 0.12 in 2024 to a central estimate of 0.06 (95% range 0.02–0.10). A 5-year backtest shows a typical error of ±42.1%, with 60% of held-out values landing inside the 95% band.19692029
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 →
20250.050.020.09
20260.060.020.09
20270.060.020.10
20280.060.020.10
20290.060.020.10

Routes In Southeastern Coastal Plain

Routes recording Tree Swallow 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 →
LovelacevileKENTUCKY62022
Lloyd XroadsNORTH-CAROLINA62001
BethelNORTH-CAROLINA52018
SurryVIRGINIA52006
MansfieldTENNESSEE42024
NewsomsVIRGINIA42024
St FlorianALABAMA32024
BlountstownFLORIDA32019
TupeloMISSISSIPPI32022
WhitevilleTENNESSEE32013
WhitehallALABAMA22009
CarrolltonALABAMA21996
GastonburgALABAMA22016
PittsGEORGIA21990
Big OakGEORGIA22024
ShilohKENTUCKY22021
CockrumMISSISSIPPI22021
MaconMISSISSIPPI22007
AberdeenMISSISSIPPI22022
RoseboroNORTH-CAROLINA21998
JacksonNORTH-CAROLINA22017
Old TrapNORTH-CAROLINA22011
Cypress LakesNORTH-CAROLINA22017
BrownsvilleTENNESSEE22000
GreensboroALABAMA12021

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