BirdAnalyst
Species · Virginia · BBS 2026 Release · 1966–2025

Cliff Swallow Population Trend in Virginia

All statesAerial insectivores

Cliff Swallow in Virginia has surged: up 171% on the route-weighted index since 1969.

+171%Since 1969TrendPercent 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 →
23Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Cliff Swallow Trends in VirginiaNotable 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 Virginia: up 171% on the route-weighted index since 1969.

Cliff Swallow Population Forecast in Virginia

If the recent trend holds, Cliff Swallow in Virginia is projected to rise about 101% by 2030 — from 1.2 in 2025 to a central estimate of 2.5 (95% range 0.47–4.5). A 5-year backtest shows a typical error of ±215.7%, with 40% of held-out values landing inside the 95% band.

+101%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 →
2.5Projected 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 →
0.47–4.595% 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 →
±215.7%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 Virginia is projected to rise about 101% by 2030 — from 1.2 in 2025 to a central estimate of 2.5 (95% range 0.47–4.5). A 5-year backtest shows a typical error of ±215.7%, with 40% of held-out values landing inside the 95% band.19662030
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 →
20262.30.304.3
20272.40.354.4
20282.40.394.4
20292.40.434.4
20302.50.474.5

Cliff Swallow Survey Routes in Virginia

Routes recording Cliff Swallow in Virginia.
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 →
Wylliesburg22020191998
Port Royal5220192008
Stanley2020251978
Gladys1820251994
Brodnax1420251975
Finchley820212007
Churchville720251966
Star Tannery619831977
W Augusta419851969
Rural Retrt420142014
Concord420242023
Hall419821982
Taylorstown219851969
Jerome220182018
Covington219661966
Covesville220191977
Carters Brdg219871969
Shipman219701970
Moran220242024
Tryme119901976
Edinburg120232014
Natural Brid119871987
Branchville120142014

Cliff Swallow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-carolinasouth-dakotatennesseetexasutahvermontwashingtonwest-virginiawisconsinwyoming

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