BirdAnalyst
Species · BCR 29 · BBS 2026 Release · 1966–2025

Tree Swallow In Piedmont

All regionsPiedmontAerial insectivores

Tree Swallow in Piedmont has surged: up 34× on the route-weighted index since 1971.

34×Since 1971TrendPercent 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 →
106Routes 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 →
56YearsYears 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 →

No notable trend signals for Tree Swallow in Piedmont. See the full index history below.

Tree Swallow In Piedmont Population Forecast

If the recent trend holds, Tree Swallow in Piedmont is projected to rise about 56% by 2030 — from 1.2 in 2025 to a central estimate of 1.8 (95% range 1.2–2.4). A 5-year backtest shows a typical error of ±42.6%, with 60% of held-out values landing inside the 95% band.

+56%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 →
1.8Projected 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 →
1.2–2.495% 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 →
±42.6%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, Tree Swallow in Piedmont is projected to rise about 56% by 2030 — from 1.2 in 2025 to a central estimate of 1.8 (95% range 1.2–2.4). A 5-year backtest shows a typical error of ±42.6%, with 60% of held-out values landing inside the 95% band.19692030
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 →
20261.71.12.3
20271.71.12.3
20281.81.22.4
20291.81.22.4
20301.81.22.4

Routes In Piedmont

Routes recording Tree Swallow 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 →
EarltonMARYLAND122024
GuptonNORTH-CAROLINA112025
JoannaSOUTH-CAROLINA102025
Van BibberMARYLAND82013
AppomattoxVIRGINIA82023
AkronPENNSYLVANIA71997
HallVIRGINIA72025
SiloamNORTH-CAROLINA62024
Mt GretnaPENNSYLVANIA62000
DavidVIRGINIA62012
ElamsvilleVIRGINIA62016
EmmitsburgMARYLAND52025
LeolaPENNSYLVANIA52025
ProsperitySOUTH-CAROLINA52010
Carters BrdgVIRGINIA52014
Brandy StationVIRGINIA52024
EkloMARYLAND42017
ArcolaNORTH-CAROLINA42025
MonticelloNORTH-CAROLINA42025
AmherstVIRGINIA42025
Church RoadVIRGINIA42025
RinggoldVIRGINIA42025
BrodnaxVIRGINIA42025
MoranVIRGINIA42025
Lake AnnaVIRGINIA42025

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