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

Cliff Swallow In Southeastern Coastal Plain

All regionsSoutheastern Coastal PlainAerial insectivores

Cliff Swallow in Southeastern Coastal Plain has surged: up 184× on the route-weighted index since 1971.

184×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 →
103Routes 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 →
53YearsYears 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 →

Cliff Swallow has surged in Southeastern Coastal Plain: up 184× on the route-weighted index since 1971.

Forecast

If the recent trend holds, Cliff Swallow in Southeastern Coastal Plain is projected to fall about 44% by 2029 — from 10 in 2024 to a central estimate of 5.6 (95% range 2.9–8.4). A 5-year backtest shows a typical error of ±36%, with 60% of held-out values landing inside the 95% band.

-44%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 →
5.6Projected 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 →
2.9–8.495% 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 →
±36%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, Cliff Swallow in Southeastern Coastal Plain is projected to fall about 44% by 2029 — from 10 in 2024 to a central estimate of 5.6 (95% range 2.9–8.4). A 5-year backtest shows a typical error of ±36%, with 60% of held-out values landing inside the 95% band.19682029
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 →
20255.22.47.9
20265.32.58.0
20275.42.78.1
20285.52.88.2
20295.62.98.4

Routes In Southeastern Coastal Plain

Routes recording Cliff 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 →
EpesALABAMA5072024
Water ValleyMISSISSIPPI3072018
Sprott-Cahaba RivALABAMA3002014
CockrumMISSISSIPPI2882024
TupeloMISSISSIPPI1672022
DolesGEORGIA1052019
SilertonTENNESSEE1002024
Duck HillMISSISSIPPI952024
Trace NorthMISSISSIPPI942018
Grenada LakeMISSISSIPPI882019
Trace HindsMISSISSIPPI812022
MansfieldTENNESSEE802024
WeirMISSISSIPPI762024
BentonMISSISSIPPI732024
EmbryMISSISSIPPI702024
PlettenbergLOUISIANA602022
AberdeenMISSISSIPPI552024
MoscowTENNESSEE502024
ShilohKENTUCKY472024
Big SandyTENNESSEE472024
BillingsleyALABAMA402022
LovelacevileKENTUCKY362024
Lake MaryMISSISSIPPI331988
BickhamLOUISIANA322024
GastonburgALABAMA302022

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