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

Chimney Swift Population Trend in Virginia

All statesAerial insectivores

Chimney Swift in Virginia has fallen sharply: down 64% on the route-weighted index since 1968.

-64%Since 1968TrendPercent 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 →
87Routes 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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Chimney Swift 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 declinecomputed 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 →

Chimney Swift has fallen sharply in Virginia: down 64% on the route-weighted index since 1968.

Chimney Swift Population Forecast in Virginia

If the recent trend holds, Chimney Swift in Virginia is projected to fall about 24% by 2030 — from 4.5 in 2025 to a central estimate of 3.4 (95% range 0.59–6.3). A 5-year backtest shows a typical error of ±16.7%, with 100% of held-out values landing inside the 95% band.

-24%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 →
3.4Projected 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 →
0.59–6.395% 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 →
±16.7%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, Chimney Swift in Virginia is projected to fall about 24% by 2030 — from 4.5 in 2025 to a central estimate of 3.4 (95% range 0.59–6.3). A 5-year backtest shows a typical error of ±16.7%, with 100% 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 →
20263.91.16.8
20273.80.986.7
20283.70.856.5
20293.60.726.4
20303.40.596.3

Chimney Swift Survey Routes in Virginia

Routes recording Chimney Swift 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 →
Stanley2920251966
Great Falls2119761966
Edinburg2020251968
Newsoms2020241967
Irisburg1920251976
Fincastle1420251966
Wylliesburg1420191971
Taylorstown1320101967
White Stone1220251966
Hebron1020221981
Newbern919821968
Brandy Station920252017
Putnam820251969
Surry720251977
Blacksburg720251988
Tryme620251975
David620131968
Shipman620251969
Ivanhoe619681966
Port Royal520251977
Waverly519871967
Church Road520251966
Sharps520251967
Quinby520251966
Marion519821976

Chimney Swift Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontwest-virginiawisconsinwyoming

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